Fancy Vivid and Fancy Intense Blue Diamond
Except otherwise stated, all results include the premium.
See also : Jewels
Chronology : 1970 1999 21st century 2010-2019 2014 2020 to now 2020 2021
See also : Jewels
Chronology : 1970 1999 21st century 2010-2019 2014 2020 to now 2020 2021
Intro
Type IIb diamonds are less than 0.5 % of the diamonds. Their most important source is the Cullinan mine in South Africa. The IIb includes the 70.21 carat Idols' Eye and the 45.52 carat Hope.
IIb diamonds have traces of boron. Micro-traces of radio-active elements enable to date the process and get information of surrounding minerals during the formation.
Their blue color is related to exposure to high pressure during the geological process which began 3.5 billion years ago at a depth of 400 to 600 kilometers within the Earth, 3 times deeper than other diamonds. The distortion of the crystal during the formation can be detected as patterns of bright interference colors when the diamond is viewed at high magnification through polarizing filters.
Blue diamonds usually occur as irregular, asymmetrical crystals. The color may be unevenly distributed throughout the rough crystal, requiring a high skill in the cutting and polishing.
They have a high electric conductivity.
On May 14, 2025, Christie's established a new record per carat for a fancy deep blue diamond weighing 6.24 carats of VVS2 clarity, potentially Internally Flawless, Type IIb, emerald-cut in a surrounding of round rubies and baguette-cut diamonds on a platinum ballerina ring signed by Boucheron. It was sold for CHF 10.6M which is CHF 1.7M per carat worth US $ 2M at that time, lot 19.
Why is the fancy vivid blue diamond considered as better than any other blue ? Some diamonds with other blue hues could be upgraded to fancy vivid blue : why and how ?
Fancy Vivid Blue Diamonds
Fancy Vivid Blue diamonds are considered superior to other blue hues because of their peak color saturation, rarity, and prestige. Blue diamonds are already among the rarest fancy colors, often caused by boron impurities, and the Fancy Vivid grade indicates the most intense, pure blue without grayish undertones or dilution. This makes them exponentially more valuable than Fancy Light or Fancy Intense Blues, as higher boron content leads to bolder hues that command top prices in the market. Vivid Blues also tend to exhibit more color depth compared to Intense grades, which may have slightly more white light return but less saturation.
Diamonds with other blue hues (or non-blue like yellow or gray) can be upgraded to Fancy Vivid Blue through similar enhancement techniques, driven by the goal of achieving that elite saturation for rarity and value. Natural blues are scarce, so treatments bridge the gap for more accessible options, though again, treated stones are valued lower. Methods include:
I guess that the capability for upgrading to fancy vivid remains scarce ?
Scarcity of Upgrading CapabilityYes, the capability to upgrade to Fancy Vivid Blue remains scarce. Technologies exist and are used for lower-grade enhancements, but vivid outcomes are rare due to dependencies on starting material (e.g., boron content), process variability, and risks like residual greenish casts or heat sensitivity. Natural vivid blues are exceptionally rare (<0.1% of mined diamonds), and successful treated upgrades are uncommon, as most enhancements produce less intense or unstable colors, requiring rare precision and suitable rough for elite results.
IIb diamonds have traces of boron. Micro-traces of radio-active elements enable to date the process and get information of surrounding minerals during the formation.
Their blue color is related to exposure to high pressure during the geological process which began 3.5 billion years ago at a depth of 400 to 600 kilometers within the Earth, 3 times deeper than other diamonds. The distortion of the crystal during the formation can be detected as patterns of bright interference colors when the diamond is viewed at high magnification through polarizing filters.
Blue diamonds usually occur as irregular, asymmetrical crystals. The color may be unevenly distributed throughout the rough crystal, requiring a high skill in the cutting and polishing.
They have a high electric conductivity.
On May 14, 2025, Christie's established a new record per carat for a fancy deep blue diamond weighing 6.24 carats of VVS2 clarity, potentially Internally Flawless, Type IIb, emerald-cut in a surrounding of round rubies and baguette-cut diamonds on a platinum ballerina ring signed by Boucheron. It was sold for CHF 10.6M which is CHF 1.7M per carat worth US $ 2M at that time, lot 19.
Why is the fancy vivid blue diamond considered as better than any other blue ? Some diamonds with other blue hues could be upgraded to fancy vivid blue : why and how ?
Fancy Vivid Blue Diamonds
Fancy Vivid Blue diamonds are considered superior to other blue hues because of their peak color saturation, rarity, and prestige. Blue diamonds are already among the rarest fancy colors, often caused by boron impurities, and the Fancy Vivid grade indicates the most intense, pure blue without grayish undertones or dilution. This makes them exponentially more valuable than Fancy Light or Fancy Intense Blues, as higher boron content leads to bolder hues that command top prices in the market. Vivid Blues also tend to exhibit more color depth compared to Intense grades, which may have slightly more white light return but less saturation.
Diamonds with other blue hues (or non-blue like yellow or gray) can be upgraded to Fancy Vivid Blue through similar enhancement techniques, driven by the goal of achieving that elite saturation for rarity and value. Natural blues are scarce, so treatments bridge the gap for more accessible options, though again, treated stones are valued lower. Methods include:
- Radiation Treatment: Controlled exposure to radiation (e.g., neutron or electron) can introduce or enhance blue color by creating defects in the crystal lattice, often followed by annealing to stabilize the vivid hue.
- HPHT Treatment: High pressure and temperature can permanently shift the color toward a more vivid blue, especially effective for off-color diamonds.
- Coating: Applying a thin blue layer (e.g., sputtered material) enhances the appearance, but it's not permanent and requires reapplication over time.
- Recutting: Optimizing the cut (e.g., to oval or pear) can amplify light play and intensify the blue, potentially upgrading from Fancy Intense to Vivid.
I guess that the capability for upgrading to fancy vivid remains scarce ?
Scarcity of Upgrading CapabilityYes, the capability to upgrade to Fancy Vivid Blue remains scarce. Technologies exist and are used for lower-grade enhancements, but vivid outcomes are rare due to dependencies on starting material (e.g., boron content), process variability, and risks like residual greenish casts or heat sensitivity. Natural vivid blues are exceptionally rare (<0.1% of mined diamonds), and successful treated upgrades are uncommon, as most enhancements produce less intense or unstable colors, requiring rare precision and suitable rough for elite results.
Significance of the Cullinan Mine in Colored Diamonds
While famed for the massive colorless Cullinan rough, the mine is the world's most important source of natural blue diamonds (Type IIb, colored by trace boron). These ultra-rare gems (<0.0001% of production) include auction legends like:
Formed deep in Earth's mantle transition zone (~410–660 km) and erupted ~1.18 billion years ago, the pipe's stability yields large, high-quality stones. Petra's stewardship emphasizes ethical sourcing, community impact, and recovery of "once-in-a-generation" treasures amid global colored diamond scarcity.
While famed for the massive colorless Cullinan rough, the mine is the world's most important source of natural blue diamonds (Type IIb, colored by trace boron). These ultra-rare gems (<0.0001% of production) include auction legends like:
- Oppenheimer Blue (14.62 ct Fancy Vivid Blue, 2016 CHF 57M — believed from Cullinan/Cullinan-linked sources via De Beers/Oppenheimer ties).
- De Beers Cullinan Blue (15.10 ct Fancy Vivid Blue, 2021 discovery, auctioned high).
- Recent finds: 39.34 ct rough blue (2021, sold ~US$40M), and a remarkable 41.82 ct Type IIb blue (January 2026 announcement by Petra Diamonds, exceptional color/clarity, potentially record-setting).
Pinks and other vivids appear occasionally, but blues dominate the colored output, contrasting with pink-heavy mines like Argyle (closed 2020). Cullinan's blues often achieve top per-carat premiums due to saturation, clarity, and provenance.
Formed deep in Earth's mantle transition zone (~410–660 km) and erupted ~1.18 billion years ago, the pipe's stability yields large, high-quality stones. Petra's stewardship emphasizes ethical sourcing, community impact, and recovery of "once-in-a-generation" treasures amid global colored diamond scarcity.
Special Report
Recent findings about the formation process
The Mediterranean Blue was a principal support for a 2024 monograph by the GIA about their formation process. This fancy vivid blue diamond of VS2 clarity weighing 10.03 carats was sold for CHF 18M by Sotheby's on May 13 2025, lot 602. Please watch the video shared by the auction house.
Overview of Type IIb Diamonds
Type IIb diamonds represent less than 0.5% of all natural diamonds and are distinguished by their boron impurities, which impart blue coloration and unique semiconducting properties. These diamonds originate from extreme depths in the Earth's mantle, far deeper than most other diamonds.
The 2024 GIA Monograph and New Findings
The 2024 GIA monograph, prepared exclusively to accompany the Mediterranean Blue diamond, synthesizes recent scientific advancements on the formation of Type IIb blue diamonds. Drawing from a comprehensive 2024 review by Shirey et al. in the Annual Review of Earth and Planetary Sciences, the monograph highlights how these diamonds form in the sublithospheric mantle at depths of 360–800 km, encompassing the asthenosphere, transition zone, and uppermost lower mantle. This is nearly four times deeper than the typical 150–200 km depths for lithospheric diamonds.
Key new insights include:
Role of the Mediterranean Blue Diamond
The Mediterranean Blue, a 10.03-carat Fancy Vivid Blue diamond discovered in 2023 at South Africa's Cullinan Mine (from a 31.94-carat rough), served as the principal support for the monograph. Its exceptional size, clarity, and color saturation enabled over a year of detailed analysis, including chemical composition, spectroscopy, and grading, which maximized insights into boron incorporation and deep origins. The Cullinan Mine is renowned for producing superdeep Type II diamonds (e.g., the Cullinan itself), and this specimen provided pristine inclusions that directly evidenced sublithospheric processes.
Why Findings Were Not Achieved Before Its Availability
Prior to the 2023 discovery of the Mediterranean Blue, such detailed insights were limited by the rarity of suitable specimens and technological constraints. While foundational ideas about superdeep origins and boron subduction emerged in the 2010s, confirming them required advanced analytical techniques (e.g., high-resolution spectroscopy and inclusion dating) applied to high-quality samples. Earlier diamonds often lacked the combination of size, purity, and well-preserved inclusions needed for comprehensive study. The monograph was developed specifically for this diamond, leveraging its unique attributes to apply and expand on the 2024 Shirey et al. review, which itself synthesized recent data unavailable in prior decades. Without this particular stone's availability for over six months of craftsmanship and in-depth research, the GIA could not have tied these global mantle models to such a vivid, real-world example.
Overview of Type IIb Diamonds
Type IIb diamonds represent less than 0.5% of all natural diamonds and are distinguished by their boron impurities, which impart blue coloration and unique semiconducting properties. These diamonds originate from extreme depths in the Earth's mantle, far deeper than most other diamonds.
The 2024 GIA Monograph and New Findings
The 2024 GIA monograph, prepared exclusively to accompany the Mediterranean Blue diamond, synthesizes recent scientific advancements on the formation of Type IIb blue diamonds. Drawing from a comprehensive 2024 review by Shirey et al. in the Annual Review of Earth and Planetary Sciences, the monograph highlights how these diamonds form in the sublithospheric mantle at depths of 360–800 km, encompassing the asthenosphere, transition zone, and uppermost lower mantle. This is nearly four times deeper than the typical 150–200 km depths for lithospheric diamonds.
Key new insights include:
- Link to Plate Tectonics and Subduction: Type IIb diamonds crystallize in carbon-rich fluids within subducted oceanic slabs. Boron, abundant in seawater-altered oceanic crust, is transported deep into the mantle via plate subduction, where it incorporates into the diamond lattice during growth. This establishes a direct "natural connection" between blue diamonds and oceanic waters, as the boron originates from ancient seawater interactions with crustal rocks.
- Evidence from Inclusions: These diamonds preserve high-pressure mineral assemblages and fluid inclusions that record mantle dynamics over billions of years, providing snapshots of large-scale geological processes like slab recycling and deep carbon cycling.
- Rarity and Conditions: The extreme pressures and specific chemical environments required make their formation rare and nearly impossible to replicate, explaining their scarcity.
Role of the Mediterranean Blue Diamond
The Mediterranean Blue, a 10.03-carat Fancy Vivid Blue diamond discovered in 2023 at South Africa's Cullinan Mine (from a 31.94-carat rough), served as the principal support for the monograph. Its exceptional size, clarity, and color saturation enabled over a year of detailed analysis, including chemical composition, spectroscopy, and grading, which maximized insights into boron incorporation and deep origins. The Cullinan Mine is renowned for producing superdeep Type II diamonds (e.g., the Cullinan itself), and this specimen provided pristine inclusions that directly evidenced sublithospheric processes.
Why Findings Were Not Achieved Before Its Availability
Prior to the 2023 discovery of the Mediterranean Blue, such detailed insights were limited by the rarity of suitable specimens and technological constraints. While foundational ideas about superdeep origins and boron subduction emerged in the 2010s, confirming them required advanced analytical techniques (e.g., high-resolution spectroscopy and inclusion dating) applied to high-quality samples. Earlier diamonds often lacked the combination of size, purity, and well-preserved inclusions needed for comprehensive study. The monograph was developed specifically for this diamond, leveraging its unique attributes to apply and expand on the 2024 Shirey et al. review, which itself synthesized recent data unavailable in prior decades. Without this particular stone's availability for over six months of craftsmanship and in-depth research, the GIA could not have tied these global mantle models to such a vivid, real-world example.
The Oppenheimer by Verdura
2016 SOLD for CHF 57M by Christie's
Throughout the twentieth century the De Beers cartel managed to control the diamond trade, accumulating an immeasurable wealth. The trust becomes a family business when a former buyer of diamonds of German origin named Ernest Oppenheimer becomes chairman of the company in 1929.
London is a hub for international operations and price controls. Sir Philip Oppenheimer retired in 1993 after 45 years as head of the Central Selling Organization of the cartel. This powerful position enabled him to keep exceptional gems.
On May 18, 2016, Christie's sold as lot 242 for CHF 57M from a lower estimate of CHF 38M the Oppenheimer Blue that had belonged to Sir Philip. Weighing 14.62 carats, it was in period the largest fancy vivid blue diamond ever offered at auction. It has been set on a ring by Verdura.
The clarity of the Oppenheimer Blue is excellent, graded VVS1 by the GIA. However, it does not reach the absolute purity of the Blue Moon, sold for CHF 49M by Sotheby's in 2015, whose stunning clarity generates a phosphorescence effect under ultraviolet radiation.
The exceptional saturation characterizing the fancy vivid blue hue is enhanced on the Oppenheimer Blue by a highly efficient rectangular cut.
I invite you to admire this masterpiece of jewelry in the video shared by Christie's.
The Oppenheimer Blue Auction Story – A Record-Setting Fancy Vivid Blue Triumph
The Oppenheimer Blue stands as one of the most iconic colored diamond sales in auction history, marking a pivotal moment in the 21st-century surge of fancy vivid blues. This 14.62-carat rectangular emerald-cut (step-cut) Fancy Vivid Blue, VVS1 diamond (GIA certified, Type IIb) sold for CHF 56.837M (US$57.5M–$57.6M including buyer's premium) at Christie's Magnificent Jewels auction in Geneva on May 18, 2016. At the time, it set the world record for the most expensive jewel or diamond ever sold at auction, surpassing the Blue Moon of Josephine's ~US$48.5M (2015) and holding the crown until the Pink Star's HK$553M (US$71.2M) in 2017.
Provenance and Historical Significance
Named in honor of its previous owner, Sir Philip Oppenheimer (1911–1995), the legendary chairman of De Beers Consolidated Mines who led the diamond industry for decades. Sir Philip, from the Oppenheimer family dynasty tied to De Beers' dominance, selected this stone personally for his wife—despite having access to the world's finest diamonds over 50+ years. This elite "connoisseur's choice" provenance added immense prestige: as François Curiel (Christie's chairman) noted, "Sir Philip could have had any diamond he wanted. But he chose this one, with its perfect hue, impeccable proportions and fabulous rectangular shape." The diamond is believed to originate from South Africa's Cullinan mine, a renowned source for rare blues (Type IIb, trace boron imparting the vivid color). Mounted in a platinum Verdura ring (with trapeze side diamonds and an optional original "Eight Shades" mounting), it embodied understated elegance and rarity—blue diamonds comprise ~0.0001% of production, with vivid saturation in this size extraordinarily scarce.
The Auction Drama
Pre-sale estimate: CHF 38M–45M (US$38M–$46M). Christie's positioned it as the largest Fancy Vivid Blue ever offered at auction, building hype around its rarity and lineage (preceding blues like Wittelsbach Blue CHF 24.3M in 2008, Winston Blue ~US$23.7M in 2014). The Geneva sale unfolded at the Four Seasons Hotel des Bergues amid intense global interest. Bidding opened at CHF 30M and progressed slowly over ~20–30 minutes in a tense, laughter-punctuated room (viewers noted long pauses, incremental CHF 200K jumps, and applause at million milestones). Two telephone bidders dominated after an early contender dropped at the low estimate. Christie's International Head of Jewelry Rahul Kadakia handled the gavel; the hammer fell at ~CHF 50.6M, with premium pushing the total to CHF 56.837M (US$57.5M, or ~$3.9M per carat). The packed room erupted in applause for the new record. The buyer remained anonymous (private collector), and the stone has stayed in private hands with no public resale or major exhibitions reported as of March 2026.
Market Context and Lasting Impact
London is a hub for international operations and price controls. Sir Philip Oppenheimer retired in 1993 after 45 years as head of the Central Selling Organization of the cartel. This powerful position enabled him to keep exceptional gems.
On May 18, 2016, Christie's sold as lot 242 for CHF 57M from a lower estimate of CHF 38M the Oppenheimer Blue that had belonged to Sir Philip. Weighing 14.62 carats, it was in period the largest fancy vivid blue diamond ever offered at auction. It has been set on a ring by Verdura.
The clarity of the Oppenheimer Blue is excellent, graded VVS1 by the GIA. However, it does not reach the absolute purity of the Blue Moon, sold for CHF 49M by Sotheby's in 2015, whose stunning clarity generates a phosphorescence effect under ultraviolet radiation.
The exceptional saturation characterizing the fancy vivid blue hue is enhanced on the Oppenheimer Blue by a highly efficient rectangular cut.
I invite you to admire this masterpiece of jewelry in the video shared by Christie's.
The Oppenheimer Blue Auction Story – A Record-Setting Fancy Vivid Blue Triumph
The Oppenheimer Blue stands as one of the most iconic colored diamond sales in auction history, marking a pivotal moment in the 21st-century surge of fancy vivid blues. This 14.62-carat rectangular emerald-cut (step-cut) Fancy Vivid Blue, VVS1 diamond (GIA certified, Type IIb) sold for CHF 56.837M (US$57.5M–$57.6M including buyer's premium) at Christie's Magnificent Jewels auction in Geneva on May 18, 2016. At the time, it set the world record for the most expensive jewel or diamond ever sold at auction, surpassing the Blue Moon of Josephine's ~US$48.5M (2015) and holding the crown until the Pink Star's HK$553M (US$71.2M) in 2017.
Provenance and Historical Significance
Named in honor of its previous owner, Sir Philip Oppenheimer (1911–1995), the legendary chairman of De Beers Consolidated Mines who led the diamond industry for decades. Sir Philip, from the Oppenheimer family dynasty tied to De Beers' dominance, selected this stone personally for his wife—despite having access to the world's finest diamonds over 50+ years. This elite "connoisseur's choice" provenance added immense prestige: as François Curiel (Christie's chairman) noted, "Sir Philip could have had any diamond he wanted. But he chose this one, with its perfect hue, impeccable proportions and fabulous rectangular shape." The diamond is believed to originate from South Africa's Cullinan mine, a renowned source for rare blues (Type IIb, trace boron imparting the vivid color). Mounted in a platinum Verdura ring (with trapeze side diamonds and an optional original "Eight Shades" mounting), it embodied understated elegance and rarity—blue diamonds comprise ~0.0001% of production, with vivid saturation in this size extraordinarily scarce.
The Auction Drama
Pre-sale estimate: CHF 38M–45M (US$38M–$46M). Christie's positioned it as the largest Fancy Vivid Blue ever offered at auction, building hype around its rarity and lineage (preceding blues like Wittelsbach Blue CHF 24.3M in 2008, Winston Blue ~US$23.7M in 2014). The Geneva sale unfolded at the Four Seasons Hotel des Bergues amid intense global interest. Bidding opened at CHF 30M and progressed slowly over ~20–30 minutes in a tense, laughter-punctuated room (viewers noted long pauses, incremental CHF 200K jumps, and applause at million milestones). Two telephone bidders dominated after an early contender dropped at the low estimate. Christie's International Head of Jewelry Rahul Kadakia handled the gavel; the hammer fell at ~CHF 50.6M, with premium pushing the total to CHF 56.837M (US$57.5M, or ~$3.9M per carat). The packed room erupted in applause for the new record. The buyer remained anonymous (private collector), and the stone has stayed in private hands with no public resale or major exhibitions reported as of March 2026.
Market Context and Lasting Impact
- Record Breakdown: It eclipsed prior blue benchmarks and became the highest-priced single diamond/jewel until the Pink Star overtook it. Per-carat ~$3.9M highlighted vivid blue premiums amid supply constraints.
- Broader Surge Tie-In: The sale fueled the "overwhelming rise" of fancy vivid coloreds (pinks/blues dominating top 10s), with Asian and ultra-high-net-worth demand driving prices. It validated provenance as a multiplier—royal/industrial ties (like Oppenheimers) adding narrative allure.
- Comparison: Outpaced contemporaries like the Pink Legacy (CHF 50M, 2018) in total at the moment but later surpassed by larger pinks. No vivid blue has reclaimed the overall jewel record since.
- Legacy: Symbolizes blue diamonds' ascent from historical curiosities (e.g., Hope Diamond) to modern investment icons. Its vivid saturation, flawless clarity, and elite history cemented it as "one of the rarest gems in the world."
The 14.62 carat Oppenheimer Blue, is one of the largest Fancy Vivid blue diamonds ever sold at auction. It was named after its previous owner, Sir Philip Oppenheimer, whose family controlled the De Beers Group. Learn more: https://t.co/g6fTgHjtMk Courtesy: Christie's Images pic.twitter.com/Y8qX4kwIwL
— GIA (@GIAnews) January 28, 2021
Bleu Royal
2023 SOLD for CHF 39.5M by Christie's
Weighing 17.61 carats and 14.2 grams, Bleu Royal is the biggest internally flawless fancy vivid blue diamond ever listed at auction, 2.99 carats more than the VVS1 Oppenheimer Blue sold for CHF 57M by Christie's in 2016.
Pear shaped and brilliant faceted, and perfectly symmetrical, Bleu Royal belonged for half a century to a private collection. It is now fitted on a platinum and 18k rose gold ring between two D-color internally flawless diamonds of 3.12 ad 3.07 carats.
Bleu Royal was sold for CHF 39.5M by Christie's on November 7, 2023, lot 87.
History of the Bleu Royal diamond
The Bleu Royal is a rare 17.61-carat pear brilliant-cut diamond, graded as Fancy Vivid Blue (the highest color intensity for blue diamonds) and Internally Flawless (IF) in clarity by the Gemological Institute of America (GIA). It belongs to the Type IIb category, which accounts for less than 0.5% of all diamonds and is characterized by the presence of boron atoms that impart the blue hue; overall, blue diamonds represent under 0.02% of mined diamonds, making Fancy Vivid examples exceptionally scarce. The stone measures approximately 25.36 x 21.78 x 9.35 mm and features precise faceting that balances the marquise and round brilliant cuts, enhancing its vivid color saturation while preserving its size—a challenging feat for colored diamonds. It was presented as a ring, flanked by two pear-shaped D-color, IF white diamonds of about 3 carats each.
Blue diamonds like the Bleu Royal form deep within the Earth's mantle under extreme pressure, where trace boron replaces carbon atoms in the crystal lattice, creating the color. However, specific details about its mining origin or discovery—such as the exact mine or country—are not publicly documented, as is common for many high-value gems with private histories. Many historic blue diamonds trace back to regions like India's Golconda mines or South Africa's Cullinan mine, but no such provenance has been disclosed for this stone.
Prior to its public debut, the Bleu Royal remained in an important private collection for approximately 50 years, with no records of prior ownership, sales, or notable events available. This anonymity is typical for ultra-rare gems, shielding owners from scrutiny while the diamond was likely held as an investment or heirloom.
The diamond entered the public spotlight in 2023 when it was consigned to Christie's for its first-ever auction appearance. It headlined the Magnificent Jewels sale during Geneva Luxury Week on November 7, 2023, at the Four Seasons Hotel des Bergues, with a pre-sale estimate of US$35-50 million (available upon request). Bidding opened at CHF 19 million and intensified among three telephone bidders, lasting about seven minutes before hammering at CHF 34 million. Including buyer's premium, it sold for CHF 39,505,000 (approximately US$43.8-44 million) to an anonymous Asian buyer represented by Isaac Choi, General Manager for South China at Christie's. This marked its transition to a new private collection after decades in seclusion.
As the largest IF Fancy Vivid Blue diamond ever offered at auction—and one of fewer than 10 blue diamonds over 10 carats to appear publicly—it ranks among the rarest gems in history, surpassing predecessors like the 10.95-carat Bulgari Blue (sold for US$15.8 million in 2010) in size but falling short of records like the 14.62-carat Oppenheimer Blue (US$57.5 million in 2016). The sale underscored the escalating demand for top-tier colored diamonds amid limited supply, cementing the Bleu Royal's status as a "miracle of nature" and the most expensive jewel auctioned in 2023.
Pear shaped and brilliant faceted, and perfectly symmetrical, Bleu Royal belonged for half a century to a private collection. It is now fitted on a platinum and 18k rose gold ring between two D-color internally flawless diamonds of 3.12 ad 3.07 carats.
Bleu Royal was sold for CHF 39.5M by Christie's on November 7, 2023, lot 87.
History of the Bleu Royal diamond
The Bleu Royal is a rare 17.61-carat pear brilliant-cut diamond, graded as Fancy Vivid Blue (the highest color intensity for blue diamonds) and Internally Flawless (IF) in clarity by the Gemological Institute of America (GIA). It belongs to the Type IIb category, which accounts for less than 0.5% of all diamonds and is characterized by the presence of boron atoms that impart the blue hue; overall, blue diamonds represent under 0.02% of mined diamonds, making Fancy Vivid examples exceptionally scarce. The stone measures approximately 25.36 x 21.78 x 9.35 mm and features precise faceting that balances the marquise and round brilliant cuts, enhancing its vivid color saturation while preserving its size—a challenging feat for colored diamonds. It was presented as a ring, flanked by two pear-shaped D-color, IF white diamonds of about 3 carats each.
Blue diamonds like the Bleu Royal form deep within the Earth's mantle under extreme pressure, where trace boron replaces carbon atoms in the crystal lattice, creating the color. However, specific details about its mining origin or discovery—such as the exact mine or country—are not publicly documented, as is common for many high-value gems with private histories. Many historic blue diamonds trace back to regions like India's Golconda mines or South Africa's Cullinan mine, but no such provenance has been disclosed for this stone.
Prior to its public debut, the Bleu Royal remained in an important private collection for approximately 50 years, with no records of prior ownership, sales, or notable events available. This anonymity is typical for ultra-rare gems, shielding owners from scrutiny while the diamond was likely held as an investment or heirloom.
The diamond entered the public spotlight in 2023 when it was consigned to Christie's for its first-ever auction appearance. It headlined the Magnificent Jewels sale during Geneva Luxury Week on November 7, 2023, at the Four Seasons Hotel des Bergues, with a pre-sale estimate of US$35-50 million (available upon request). Bidding opened at CHF 19 million and intensified among three telephone bidders, lasting about seven minutes before hammering at CHF 34 million. Including buyer's premium, it sold for CHF 39,505,000 (approximately US$43.8-44 million) to an anonymous Asian buyer represented by Isaac Choi, General Manager for South China at Christie's. This marked its transition to a new private collection after decades in seclusion.
As the largest IF Fancy Vivid Blue diamond ever offered at auction—and one of fewer than 10 blue diamonds over 10 carats to appear publicly—it ranks among the rarest gems in history, surpassing predecessors like the 10.95-carat Bulgari Blue (sold for US$15.8 million in 2010) in size but falling short of records like the 14.62-carat Oppenheimer Blue (US$57.5 million in 2016). The sale underscored the escalating demand for top-tier colored diamonds amid limited supply, cementing the Bleu Royal's status as a "miracle of nature" and the most expensive jewel auctioned in 2023.
WATCH: The vivid blue diamond 'Bleu Royal' - which is set in a ring - is among the rarest ever to be unearthed. At 17.6 carats, it is also the largest of its kind https://t.co/3phvuSzqDa pic.twitter.com/goMk9iZhkq
— Reuters Asia (@ReutersAsia) November 2, 2023
1970 Laguna Blu by Bulgari
2023 SOLD for CHF 22.6M by Sotheby's
Laguna Blu is a ring mounted by Bulgari with a fancy vivid blue diamond between tapered diamond shoulders. The blue diamond is pear shaped. It weighs 11.16 carats with a VS1 clarity. The ring was sold from the collection of its first owner for CHF 22.6M by Sotheby's on May 16, 2023, lot 675.
The Bulgari Laguna Blu is an exceptional 11.16-carat pear-shaped Fancy Vivid Blue diamond, graded by the Gemological Institute of America (GIA) as the highest and rarest color grade for a blue diamond, with an internally flawless clarity. Its name evokes an oceanic blue hue, and its large size makes it extraordinarily rare—fewer than ten Fancy Vivid Blue diamonds over 10 carats have appeared at auction in recent decades.
The diamond was commissioned from Bulgari in 1970 and set into a ring by the Italian jewelry house (part of the LVMH group) for a distinguished private European collector. This occurred during a transformative era for Bulgari, when the Roman brand was rising to prominence in Hollywood glamour and colored gemstones, becoming a favorite of stars like Elizabeth Taylor. It was part of a larger consignment that included other signed Bulgari pieces from the early 1970s, such as a 12.08-carat pear-shaped white diamond and an 18.78-carat step-cut white diamond.
The Laguna Blu remained unmodified and in the possession of the same family for over 50 years, preserving its original 1970 cut despite advancements in diamond polishing technology that could have potentially enhanced it further. No public details are available about the diamond's origin prior to 1970, such as its mining source (blue diamonds historically often trace back to regions like South Africa or India, but this is unconfirmed for the Laguna Blu).
In early May 2023, the diamond made a high-profile public debut when Sotheby's loaned it to Bulgari, who remounted it temporarily as the centerpiece of a custom high jewelry necklace inspired by Greco-Roman bay laurel wreaths, featuring interlocking baguette and pavé diamonds set in platinum. It was worn by Indian actress and Bulgari global ambassador Priyanka Chopra Jonas at the Met Gala in New York on May 1, 2023, generating significant media attention.
Shortly after, the diamond was returned to its original ring setting and displayed for five days at the Mandarin Oriental in Geneva prior to auction. On May 16, 2023, it headlined Sotheby's Magnificent Jewels and Noble Jewels sale in Geneva, where it sparked a four-minute bidding war among one in-room bidder and three telephone participants. It sold for $25.2 million to a remote bidder, marking the first ownership change in over five decades and setting a record as the most valuable gem ever set in a Bulgari jewel at auction. The sale contributed to Sotheby's achieving its best jewelry auction performance in five years, totaling $85 million across 133 lots.
No further public auctions, ownership changes, or major events involving the Laguna Blu have been reported since the 2023 sale, though retrospective articles in 2025 have highlighted its enduring legacy as one of the world's most iconic blue diamonds.
The Bulgari Laguna Blu is an exceptional 11.16-carat pear-shaped Fancy Vivid Blue diamond, graded by the Gemological Institute of America (GIA) as the highest and rarest color grade for a blue diamond, with an internally flawless clarity. Its name evokes an oceanic blue hue, and its large size makes it extraordinarily rare—fewer than ten Fancy Vivid Blue diamonds over 10 carats have appeared at auction in recent decades.
The diamond was commissioned from Bulgari in 1970 and set into a ring by the Italian jewelry house (part of the LVMH group) for a distinguished private European collector. This occurred during a transformative era for Bulgari, when the Roman brand was rising to prominence in Hollywood glamour and colored gemstones, becoming a favorite of stars like Elizabeth Taylor. It was part of a larger consignment that included other signed Bulgari pieces from the early 1970s, such as a 12.08-carat pear-shaped white diamond and an 18.78-carat step-cut white diamond.
The Laguna Blu remained unmodified and in the possession of the same family for over 50 years, preserving its original 1970 cut despite advancements in diamond polishing technology that could have potentially enhanced it further. No public details are available about the diamond's origin prior to 1970, such as its mining source (blue diamonds historically often trace back to regions like South Africa or India, but this is unconfirmed for the Laguna Blu).
In early May 2023, the diamond made a high-profile public debut when Sotheby's loaned it to Bulgari, who remounted it temporarily as the centerpiece of a custom high jewelry necklace inspired by Greco-Roman bay laurel wreaths, featuring interlocking baguette and pavé diamonds set in platinum. It was worn by Indian actress and Bulgari global ambassador Priyanka Chopra Jonas at the Met Gala in New York on May 1, 2023, generating significant media attention.
Shortly after, the diamond was returned to its original ring setting and displayed for five days at the Mandarin Oriental in Geneva prior to auction. On May 16, 2023, it headlined Sotheby's Magnificent Jewels and Noble Jewels sale in Geneva, where it sparked a four-minute bidding war among one in-room bidder and three telephone participants. It sold for $25.2 million to a remote bidder, marking the first ownership change in over five decades and setting a record as the most valuable gem ever set in a Bulgari jewel at auction. The sale contributed to Sotheby's achieving its best jewelry auction performance in five years, totaling $85 million across 133 lots.
No further public auctions, ownership changes, or major events involving the Laguna Blu have been reported since the 2023 sale, though retrospective articles in 2025 have highlighted its enduring legacy as one of the world's most iconic blue diamonds.
1999 The Millennium 4
2016 SOLD for HK$ 250M by Sotheby's
De Beers exhibited their finest diamonds at the Millennium Dome in London throughout the year 2000. The Millennium Star is an astonishing white diamond weighing 203.04 carats. Facing it in the cabinet, eleven blue diamonds are totaling 118 carats. All these wonders had been extracted from the Cullinan mine.
One of these blue diamonds was oval cut. Weighing 10.10 carats, it is not the largest of the eleven but it is indeed the most spectacular. It was certified Fancy Vivid Blue Flawless in 1999 by GIA with the designation De Beers Millennium Jewel 4. Mounted on a ring in a surrounding of small white diamonds, it was sold for HK $ 250M by Sotheby's on April 5, 2016, lot 1843.
This unprecedented treasure insured altogether for £ 350M excited high appetites during the show at the Dome. On November 7, 2000, a commando of four equipped with a ten ton earth digger, sledgehammers, smoke bombs, gas masks and bulletproof vests come into the Dome, ready to celebrate the new millennium with the biggest heist ever.
The gang was under surveillance and 200 police officers had been mobilized. The head of the counter operation had decided to let the robbers go up to the showcase window for security reasons because arrests are easier in a closed room.
Please watch the short video shared by Sotheby's.
Origin and Discovery
The De Beers Millennium Jewel 4 is a rare 10.10-carat oval-modified brilliant-cut diamond, graded as Fancy Vivid Blue and Internally Flawless by the Gemological Institute of America (GIA). Blue diamonds like this one derive their color from trace amounts of boron impurities, and they are exceptionally scarce, comprising much less than 0.1% of all diamonds recovered from the Cullinan Mine (formerly Premier Mine) in South Africa, where most high-quality blue diamonds have been sourced in the last century. While the exact discovery date of the rough stone is not publicly documented, it was mined in South Africa and selected by De Beers for special polishing in the late 1990s. De Beers collaborated with the Steinmetz Diamond Group to cut and polish it into its current form, inscribing it with "De Beers Millennium Jewel 4" using proprietary laser technology.
The De Beers Millennium Jewels Collection
This diamond was one of 11 exceptional blue diamonds (totaling 118 carats) assembled by De Beers to commemorate the new millennium, alongside the centerpiece 203.04-carat colorless Millennium Star. Nine of the blues, including Jewel 4, were graded Fancy Vivid Blue—the highest color intensity rating—while two were Fancy Intense Blue. The collection featured various shapes and sizes, from a 5.16-carat pear-shaped stone to the 27.64-carat Heart of Eternity. It was unveiled as part of the Millennium Jewels exhibition to celebrate the year 2000.
Exhibition at the Millennium Dome (1999–2000)
The diamond was publicly displayed at the Millennium Dome in Greenwich, London, starting on December 31, 1999, and continuing throughout 2000. The exhibition attracted significant attention, showcasing the collection's rarity and value, estimated at over £350 million (equivalent to about £744 million in 2023).
The Millennium Dome Heist Attempt (November 7, 2000)
On November 7, 2000, a gang of experienced criminals attempted to steal the Millennium Jewels in what could have been the largest diamond heist in history. The plot, codenamed Operation Magician by the Metropolitan Police, involved ramming the Dome's perimeter with a JCB digger, using smoke bombs, sledgehammers, nail guns, and ammonia to breach security glass, and escaping via speedboat on the River Thames. The gang, led by Raymond Betson and William Cockram, had invested tens of thousands of pounds in equipment and conducted reconnaissance, including testing speedboats and timing high tides.
Forewarned by a tip-off, police replaced the real diamonds (including Jewel 4) with replicas a day earlier and ambushed the robbers. Over 200 officers, including armed units, were involved; the gang smashed into the exhibit but was arrested on site. Key members included Betson, Cockram, Aldo Ciarrocchi, Robert Adams, Lee Wenham, and Terry Millman (who died before trial). In 2001–2002 trials at the Old Bailey, the main perpetrators were convicted of conspiracy to rob and sentenced to 15–18 years (some reduced on appeal). The heist was foiled without harm, and the originals remained safe.
Post-Exhibition and Private Ownership (2001–2015)
After the exhibition closed, the Millennium Jewels were dispersed into private hands. Jewel 4 entered an Asian private collection, where it remained out of the public eye for over a decade. During this period, only one other diamond from the collection (De Beers Millennium Jewel 11, a 5.16-carat pear-shaped Fancy Vivid Blue) appeared at auction, selling for £4.2 million at Sotheby's Hong Kong in April 2010. Jewel 4 was mentioned in literature, including The Steinmetz Diamond Story (2003).
2016 Auction at Sotheby's Hong Kong
In 2016, the diamond was offered for sale by its Asian private owner at Sotheby's Magnificent Jewels and Jadeite auction in Hong Kong on April 5. Estimated at $30–35 million, it was mounted in an 18-karat white gold ring with flanking pear-shaped and circular-cut colorless diamonds (totaling about 1.80 carats). It sold for HK$248,280,000 (approximately US$31.8 million) to an anonymous telephone bidder, setting records as the most expensive diamond ever sold in Asia, the highest price for any jewel at auction in Asia, and the largest oval Fancy Vivid Blue diamond ever auctioned. The sale reflected booming demand for colored diamonds, with blue diamond values rising over 300% in the prior decade. This occurred amid a string of record-breaking blue diamond sales, including the Blue Moon Diamond ($48.4 million in 2015) and Oppenheimer Blue ($57.5 million in 2016).
Post-2016 Ownership and Legacy
Since the 2016 sale, the diamond has remained in private hands with no public resales, exhibitions, or notable events reported as of January 2026. The buyer remains anonymous, and it has not reappeared on the market. It continues to be referenced in discussions of rare blue diamonds, such as in De Beers' own promotions of similar stones like the De Beers Cullinan Blue in 2022. Its legacy endures as a symbol of rarity—fewer than 0.02% of diamonds exhibit such vivid blue intensity—and its brush with the infamous heist adds to its storied allure.
One of these blue diamonds was oval cut. Weighing 10.10 carats, it is not the largest of the eleven but it is indeed the most spectacular. It was certified Fancy Vivid Blue Flawless in 1999 by GIA with the designation De Beers Millennium Jewel 4. Mounted on a ring in a surrounding of small white diamonds, it was sold for HK $ 250M by Sotheby's on April 5, 2016, lot 1843.
This unprecedented treasure insured altogether for £ 350M excited high appetites during the show at the Dome. On November 7, 2000, a commando of four equipped with a ten ton earth digger, sledgehammers, smoke bombs, gas masks and bulletproof vests come into the Dome, ready to celebrate the new millennium with the biggest heist ever.
The gang was under surveillance and 200 police officers had been mobilized. The head of the counter operation had decided to let the robbers go up to the showcase window for security reasons because arrests are easier in a closed room.
Please watch the short video shared by Sotheby's.
Origin and Discovery
The De Beers Millennium Jewel 4 is a rare 10.10-carat oval-modified brilliant-cut diamond, graded as Fancy Vivid Blue and Internally Flawless by the Gemological Institute of America (GIA). Blue diamonds like this one derive their color from trace amounts of boron impurities, and they are exceptionally scarce, comprising much less than 0.1% of all diamonds recovered from the Cullinan Mine (formerly Premier Mine) in South Africa, where most high-quality blue diamonds have been sourced in the last century. While the exact discovery date of the rough stone is not publicly documented, it was mined in South Africa and selected by De Beers for special polishing in the late 1990s. De Beers collaborated with the Steinmetz Diamond Group to cut and polish it into its current form, inscribing it with "De Beers Millennium Jewel 4" using proprietary laser technology.
The De Beers Millennium Jewels Collection
This diamond was one of 11 exceptional blue diamonds (totaling 118 carats) assembled by De Beers to commemorate the new millennium, alongside the centerpiece 203.04-carat colorless Millennium Star. Nine of the blues, including Jewel 4, were graded Fancy Vivid Blue—the highest color intensity rating—while two were Fancy Intense Blue. The collection featured various shapes and sizes, from a 5.16-carat pear-shaped stone to the 27.64-carat Heart of Eternity. It was unveiled as part of the Millennium Jewels exhibition to celebrate the year 2000.
Exhibition at the Millennium Dome (1999–2000)
The diamond was publicly displayed at the Millennium Dome in Greenwich, London, starting on December 31, 1999, and continuing throughout 2000. The exhibition attracted significant attention, showcasing the collection's rarity and value, estimated at over £350 million (equivalent to about £744 million in 2023).
The Millennium Dome Heist Attempt (November 7, 2000)
On November 7, 2000, a gang of experienced criminals attempted to steal the Millennium Jewels in what could have been the largest diamond heist in history. The plot, codenamed Operation Magician by the Metropolitan Police, involved ramming the Dome's perimeter with a JCB digger, using smoke bombs, sledgehammers, nail guns, and ammonia to breach security glass, and escaping via speedboat on the River Thames. The gang, led by Raymond Betson and William Cockram, had invested tens of thousands of pounds in equipment and conducted reconnaissance, including testing speedboats and timing high tides.
Forewarned by a tip-off, police replaced the real diamonds (including Jewel 4) with replicas a day earlier and ambushed the robbers. Over 200 officers, including armed units, were involved; the gang smashed into the exhibit but was arrested on site. Key members included Betson, Cockram, Aldo Ciarrocchi, Robert Adams, Lee Wenham, and Terry Millman (who died before trial). In 2001–2002 trials at the Old Bailey, the main perpetrators were convicted of conspiracy to rob and sentenced to 15–18 years (some reduced on appeal). The heist was foiled without harm, and the originals remained safe.
Post-Exhibition and Private Ownership (2001–2015)
After the exhibition closed, the Millennium Jewels were dispersed into private hands. Jewel 4 entered an Asian private collection, where it remained out of the public eye for over a decade. During this period, only one other diamond from the collection (De Beers Millennium Jewel 11, a 5.16-carat pear-shaped Fancy Vivid Blue) appeared at auction, selling for £4.2 million at Sotheby's Hong Kong in April 2010. Jewel 4 was mentioned in literature, including The Steinmetz Diamond Story (2003).
2016 Auction at Sotheby's Hong Kong
In 2016, the diamond was offered for sale by its Asian private owner at Sotheby's Magnificent Jewels and Jadeite auction in Hong Kong on April 5. Estimated at $30–35 million, it was mounted in an 18-karat white gold ring with flanking pear-shaped and circular-cut colorless diamonds (totaling about 1.80 carats). It sold for HK$248,280,000 (approximately US$31.8 million) to an anonymous telephone bidder, setting records as the most expensive diamond ever sold in Asia, the highest price for any jewel at auction in Asia, and the largest oval Fancy Vivid Blue diamond ever auctioned. The sale reflected booming demand for colored diamonds, with blue diamond values rising over 300% in the prior decade. This occurred amid a string of record-breaking blue diamond sales, including the Blue Moon Diamond ($48.4 million in 2015) and Oppenheimer Blue ($57.5 million in 2016).
Post-2016 Ownership and Legacy
Since the 2016 sale, the diamond has remained in private hands with no public resales, exhibitions, or notable events reported as of January 2026. The buyer remains anonymous, and it has not reappeared on the market. It continues to be referenced in discussions of rare blue diamonds, such as in De Beers' own promotions of similar stones like the De Beers Cullinan Blue in 2022. Its legacy endures as a symbol of rarity—fewer than 0.02% of diamonds exhibit such vivid blue intensity—and its brush with the infamous heist adds to its storied allure.
The De Beers Millennium Jewel 4, a 10.10 ct oval, Fancy Vivid blue #diamond, hits the auction block tomorrow… pic.twitter.com/yDwvRhdLh6
— GIA (@GIAnews) April 4, 2016
The Mellon Blue ex The Zoe
2014 SOLD for $ 32.6M by Sotheby's
From the collection of Mrs Paul Mellon, a blue diamond was sold for $ 32.6M from a lower estimate of $ 10M by Sotheby's on November 20, 2014, lot 37. It was referred as the Zoe after that sale.
This pear shaped fancy vivid blue weighing 9.75 carats was mounted in platinum. Its clarity is VVS2. It is accompanied by a diagram by the GIA stating that it may potentially be upgraded to Internally flawless.
It had as a pendant a fancy blue diamond of same shape and mounting, weighing 9.15 carats in VS1 clarity, which was sold for $ 2.96M in the same sale as above, lot 38.
The Zoe has been renamed the Mellon Blue. With a clarity improved to VVS1 and a weight reduced to 9.51 carats, it was sold for CHF 20.5M by Christie's on November 11, 2025, lot 50. Its shape is now referred as modified pear brilliant-cut. It is mounted in platinum as a fancy ring with a pattern of diamonds.
Origins and Early History
The exact origins of this diamond, including its mining location and initial discovery, remain unknown based on publicly available records. Fancy Vivid Blue diamonds like this one are extremely rare, deriving their color from trace amounts of boron and forming under intense geological pressure deep within the Earth. Most blue diamonds originate from the Cullinan Mine (formerly Premier Mine) in South Africa, but no specific mine has been confirmed for this stone. It is believed to have been cut and polished sometime in the mid-20th century or earlier, though details are scarce.
Acquisition by Rachel "Bunny" Lambert Mellon
The diamond entered documented history as part of the personal jewelry collection of Rachel Lambert Mellon, known as "Bunny" Mellon (1910–2014), an American heiress, philanthropist, horticulturist, and art collector. Mellon, married to banking heir and philanthropist Paul Mellon, amassed an extraordinary collection of jewelry, often from renowned designers like Jean Schlumberger for Tiffany & Co. The precise date and circumstances of her acquisition of this 9.75-carat pear-shaped Fancy Vivid Blue, Internally Flawless diamond are not publicly known, but it was likely obtained in the mid-20th century, possibly in the 1950s or 1960s, during the height of her collecting period. She wore it set as a pendant, and it was one of the highlights of her estate's jewelry holdings, valued for its exceptional color saturation and clarity.
2014 Sale at Sotheby's
Following Bunny Mellon's death on March 17, 2014, at age 103, her vast collection of art, jewelry, and decorative objects was dispersed through a series of auctions. On November 20, 2014, the diamond was offered as Lot 1845 in Sotheby's "Property from the Collection of Mrs. Paul Mellon: Jewels & Objects of Vertu" sale in New York. Described as a 9.75-carat pear-shaped Fancy Vivid Blue diamond, graded Internally Flawless by the Gemological Institute of America (GIA), it sold for $32,645,000 (including buyer's premium) after intense bidding. This shattered two world auction records: the highest price for any blue diamond ($32.6 million) and the highest price per carat for any diamond or gemstone ($3,348,205 per carat). The buyer was Hong Kong property billionaire Joseph Lau Luen-hung, who purchased it anonymously at the time but was later identified.
Renaming and Modifications (2014–2025)
Shortly after the purchase, Lau renamed the diamond "The Zoe Diamond" in honor of his daughter Zoe. Lau, a convicted fugitive (in absentia for bribery in Macau) and known collector of rare gems, had a history of buying high-value colored diamonds for his family, including the "Blue Moon of Josephine" for his other daughter. Sometime between 2014 and 2025, the diamond underwent minor retouching to enhance its clarity, which slightly reduced its weight to 9.51 carats and adjusted its cut to a modified pear brilliant. It was also reset from a pendant into a platinum ring featuring a serpentine pavé design with single-cut diamonds, and the shank was engraved with "Fancy Vivid Blue." During this period, the diamond remained in private hands and was not publicly exhibited.
2025 Sale at Christie's
In 2025, the diamond—now emphasizing its Mellon provenance and marketed as "The Mellon Blue"—was consigned for sale, likely by Joseph Lau or his representatives (though the seller's identity was not publicly confirmed). It was announced in September 2025 and offered as a highlight of Christie's Magnificent Jewels auction in Geneva on November 11, 2025. With an estimate of $20–30 million, it sold for CHF 20,525,000 (approximately $25.6 million USD, based on exchange rates at the time). The buyer remained anonymous. This sale, while below the 2014 record, underscored the diamond's enduring value and rarity, as Fancy Vivid Blue diamonds represent less than 1% of all blue diamonds submitted to the GIA. The price per carat was around $2.69 million, reflecting strong demand for colored diamonds despite market fluctuations.
Current Status (as of January 2026)
As of the current date, the diamond is in the possession of its anonymous 2025 buyer. No further public sales or exhibitions have been reported. It remains one of the most valuable and historically significant blue diamonds ever auctioned, symbolizing the intersection of elite provenance, geological rarity, and market prestige. Its value has appreciated overall since its first auction appearance, though influenced by recutting and broader economic factors in the luxury gem market.
This pear shaped fancy vivid blue weighing 9.75 carats was mounted in platinum. Its clarity is VVS2. It is accompanied by a diagram by the GIA stating that it may potentially be upgraded to Internally flawless.
It had as a pendant a fancy blue diamond of same shape and mounting, weighing 9.15 carats in VS1 clarity, which was sold for $ 2.96M in the same sale as above, lot 38.
The Zoe has been renamed the Mellon Blue. With a clarity improved to VVS1 and a weight reduced to 9.51 carats, it was sold for CHF 20.5M by Christie's on November 11, 2025, lot 50. Its shape is now referred as modified pear brilliant-cut. It is mounted in platinum as a fancy ring with a pattern of diamonds.
Origins and Early History
The exact origins of this diamond, including its mining location and initial discovery, remain unknown based on publicly available records. Fancy Vivid Blue diamonds like this one are extremely rare, deriving their color from trace amounts of boron and forming under intense geological pressure deep within the Earth. Most blue diamonds originate from the Cullinan Mine (formerly Premier Mine) in South Africa, but no specific mine has been confirmed for this stone. It is believed to have been cut and polished sometime in the mid-20th century or earlier, though details are scarce.
Acquisition by Rachel "Bunny" Lambert Mellon
The diamond entered documented history as part of the personal jewelry collection of Rachel Lambert Mellon, known as "Bunny" Mellon (1910–2014), an American heiress, philanthropist, horticulturist, and art collector. Mellon, married to banking heir and philanthropist Paul Mellon, amassed an extraordinary collection of jewelry, often from renowned designers like Jean Schlumberger for Tiffany & Co. The precise date and circumstances of her acquisition of this 9.75-carat pear-shaped Fancy Vivid Blue, Internally Flawless diamond are not publicly known, but it was likely obtained in the mid-20th century, possibly in the 1950s or 1960s, during the height of her collecting period. She wore it set as a pendant, and it was one of the highlights of her estate's jewelry holdings, valued for its exceptional color saturation and clarity.
2014 Sale at Sotheby's
Following Bunny Mellon's death on March 17, 2014, at age 103, her vast collection of art, jewelry, and decorative objects was dispersed through a series of auctions. On November 20, 2014, the diamond was offered as Lot 1845 in Sotheby's "Property from the Collection of Mrs. Paul Mellon: Jewels & Objects of Vertu" sale in New York. Described as a 9.75-carat pear-shaped Fancy Vivid Blue diamond, graded Internally Flawless by the Gemological Institute of America (GIA), it sold for $32,645,000 (including buyer's premium) after intense bidding. This shattered two world auction records: the highest price for any blue diamond ($32.6 million) and the highest price per carat for any diamond or gemstone ($3,348,205 per carat). The buyer was Hong Kong property billionaire Joseph Lau Luen-hung, who purchased it anonymously at the time but was later identified.
Renaming and Modifications (2014–2025)
Shortly after the purchase, Lau renamed the diamond "The Zoe Diamond" in honor of his daughter Zoe. Lau, a convicted fugitive (in absentia for bribery in Macau) and known collector of rare gems, had a history of buying high-value colored diamonds for his family, including the "Blue Moon of Josephine" for his other daughter. Sometime between 2014 and 2025, the diamond underwent minor retouching to enhance its clarity, which slightly reduced its weight to 9.51 carats and adjusted its cut to a modified pear brilliant. It was also reset from a pendant into a platinum ring featuring a serpentine pavé design with single-cut diamonds, and the shank was engraved with "Fancy Vivid Blue." During this period, the diamond remained in private hands and was not publicly exhibited.
2025 Sale at Christie's
In 2025, the diamond—now emphasizing its Mellon provenance and marketed as "The Mellon Blue"—was consigned for sale, likely by Joseph Lau or his representatives (though the seller's identity was not publicly confirmed). It was announced in September 2025 and offered as a highlight of Christie's Magnificent Jewels auction in Geneva on November 11, 2025. With an estimate of $20–30 million, it sold for CHF 20,525,000 (approximately $25.6 million USD, based on exchange rates at the time). The buyer remained anonymous. This sale, while below the 2014 record, underscored the diamond's enduring value and rarity, as Fancy Vivid Blue diamonds represent less than 1% of all blue diamonds submitted to the GIA. The price per carat was around $2.69 million, reflecting strong demand for colored diamonds despite market fluctuations.
Current Status (as of January 2026)
As of the current date, the diamond is in the possession of its anonymous 2025 buyer. No further public sales or exhibitions have been reported. It remains one of the most valuable and historically significant blue diamonds ever auctioned, symbolizing the intersection of elite provenance, geological rarity, and market prestige. Its value has appreciated overall since its first auction appearance, though influenced by recutting and broader economic factors in the luxury gem market.
#AuctionUpdate: At $32.6m, Mrs Mellon's Fancy Vivid Blue Diamond sets a new world #AuctionRecord for Any Blue Diamond pic.twitter.com/10VjCOFLln
— Sotheby's (@Sothebys) November 21, 2014
Apollo (The Memory of Autumn Leaves)
2017 SOLD for CHF 42M by Sotheby's
On May 16, 2017, Sotheby's sold for CHF 42M an exceptional blue diamond, lot 377. It is in the best color, Fancy vivid blue, and perfect clarity, Internally Flawless (IF). It weighs 14.54 carats, comparable with the 14.62 carats of the Oppenheimer Blue. It fetched over $2.9 million per carat—surpassing prior benchmarks for colored diamonds amid booming collector interest.
The concentration of boron atoms in its crystal made it classify as Type IIb by the GIA, rarer than the Type IIa.
This diamond is pear shaped. Someone had the idea to choose a pink diamond of comparable cut and size. The two gems hanging each to a suite of two white diamonds thus constitutes temporarily the most sumptuous pair of earrings. They are named Apollo and Artemis by reference to the beautiful twins of Greek mythology.
The pair was divided. Artemis was sold for CHF 15.3M, lot 378. It is a Fancy intense pink Type IIa and VVS2 clarity weighing 16.00 carats.
The blue Apollo is now referred as The Memory of Autumn Leaves.
History of the Apollo Blue Diamond
The Apollo Blue diamond is a 14.54-carat, pear-shaped, Fancy Vivid Blue diamond, graded as internally flawless (IF) and Type IIb by the Gemological Institute of America (GIA). Type IIb diamonds, which exhibit blue coloration due to boron impurities, represent less than 0.5% of all diamonds and are prized for their rarity and electrical conductivity.
Origin and Mining
Blue diamonds like the Apollo are typically sourced from South Africa's Cullinan Mine (formerly known as the Premier Mine), which is renowned for producing large, high-quality Type IIb blue diamonds. The mine, discovered in 1902, has yielded many iconic gems, including the historic 3,106-carat Cullinan Diamond. While the exact rough stone and mining date for the Apollo Blue are not publicly documented, its South African origin aligns with the mine's history of producing vivid blue stones, such as a 29.6-carat blue rough discovered in 2014 and a 39.34-carat blue rough acquired in 2021.
Pre-Auction History
Details on the diamond's journey from rough to polished form, including cutting and early ownership, remain private and undocumented in public records. It was likely part of a private collection before being consigned to Sotheby's, where it was paired with the Artemis Pink diamond and mounted as an earring for the auction. Sotheby's named it "Apollo Blue" after the Greek god, emphasizing its mythical rarity and pairing it with its "twin" to evoke divine power. No prior auction appearances or notable owners are recorded.2017 Auction and SaleOn May 16, 2017, at Sotheby's Magnificent Jewels and Noble Jewels sale in Geneva, the Apollo Blue sold for $42.087 million (CHF 41,483,750, including buyer's premium), setting a record for the highest price per carat for a blue diamond at over $2.9 million per carat. It was purchased by an anonymous bidder via telephone.
Post-Auction Ownership and Current Status
Immediately after the sale, the anonymous buyer renamed the diamond "The Memory of Autumn Leaves." As of January 2026, there are no records of resale, exhibitions, or further public appearances, suggesting it remains in private ownership. It continues to be referenced as one of the most expensive blue diamonds ever sold, underscoring the growing investment appeal of fancy colored diamonds.
History of the Artemis Pink Diamond
The Artemis Pink diamond is a 16-carat, pear-shaped, Fancy Intense Pink diamond, graded as VVS1 clarity by the GIA. Pink diamonds derive their color from structural distortions in the crystal lattice rather than impurities, making them exceptionally rare.
Origin and Mining
While over 90% of natural pink diamonds originate from Australia's Argyle Mine in Western Australia, which closed in 2020, some reports indicate the Artemis Pink was mined in South Africa. Pink diamonds have also been found in Brazil, Russia, Tanzania, and occasionally South Africa, though the latter is uncommon. The exact mine and discovery date are not publicly known, but geological studies suggest pink diamonds formed around 1.3 billion years ago during the breakup of the supercontinent Nuna.
Pre-Auction History
Similar to the Apollo Blue, the Artemis Pink's early history—including rough extraction, polishing, and ownership—is not detailed in available records. It was matched with the Apollo Blue by Sotheby's for the auction, mounted as an earring, and named after the Greek goddess Artemis to symbolize its ethereal beauty and rarity. It likely came from a private consignor with no prior public sales noted.
2017 Auction and Sale
At the same Sotheby's Geneva auction on May 16, 2017, the Artemis Pink sold for $15.334 million (CHF 15,120,750, including buyer's premium). The same anonymous buyer acquired it, making the pair the most expensive earrings ever sold at auction (totaling $57.4 million), though they were auctioned as separate lots.
Post-Auction Ownership and Current Status
The buyer renamed it "The Dream of Autumn Leaves" shortly after the purchase. No subsequent sales or public displays have been reported as of January 2026, indicating it stays in the same private collection. The diamond is often cited alongside its blue counterpart as a benchmark for fancy colored diamond values.Both diamonds' histories are notably private prior to 2017, with their fame stemming primarily from the record-breaking auction. They exemplify the market's enthusiasm for rare colored diamonds, driven by their scarcity and aesthetic appeal.
The concentration of boron atoms in its crystal made it classify as Type IIb by the GIA, rarer than the Type IIa.
This diamond is pear shaped. Someone had the idea to choose a pink diamond of comparable cut and size. The two gems hanging each to a suite of two white diamonds thus constitutes temporarily the most sumptuous pair of earrings. They are named Apollo and Artemis by reference to the beautiful twins of Greek mythology.
The pair was divided. Artemis was sold for CHF 15.3M, lot 378. It is a Fancy intense pink Type IIa and VVS2 clarity weighing 16.00 carats.
The blue Apollo is now referred as The Memory of Autumn Leaves.
History of the Apollo Blue Diamond
The Apollo Blue diamond is a 14.54-carat, pear-shaped, Fancy Vivid Blue diamond, graded as internally flawless (IF) and Type IIb by the Gemological Institute of America (GIA). Type IIb diamonds, which exhibit blue coloration due to boron impurities, represent less than 0.5% of all diamonds and are prized for their rarity and electrical conductivity.
Origin and Mining
Blue diamonds like the Apollo are typically sourced from South Africa's Cullinan Mine (formerly known as the Premier Mine), which is renowned for producing large, high-quality Type IIb blue diamonds. The mine, discovered in 1902, has yielded many iconic gems, including the historic 3,106-carat Cullinan Diamond. While the exact rough stone and mining date for the Apollo Blue are not publicly documented, its South African origin aligns with the mine's history of producing vivid blue stones, such as a 29.6-carat blue rough discovered in 2014 and a 39.34-carat blue rough acquired in 2021.
Pre-Auction History
Details on the diamond's journey from rough to polished form, including cutting and early ownership, remain private and undocumented in public records. It was likely part of a private collection before being consigned to Sotheby's, where it was paired with the Artemis Pink diamond and mounted as an earring for the auction. Sotheby's named it "Apollo Blue" after the Greek god, emphasizing its mythical rarity and pairing it with its "twin" to evoke divine power. No prior auction appearances or notable owners are recorded.2017 Auction and SaleOn May 16, 2017, at Sotheby's Magnificent Jewels and Noble Jewels sale in Geneva, the Apollo Blue sold for $42.087 million (CHF 41,483,750, including buyer's premium), setting a record for the highest price per carat for a blue diamond at over $2.9 million per carat. It was purchased by an anonymous bidder via telephone.
Post-Auction Ownership and Current Status
Immediately after the sale, the anonymous buyer renamed the diamond "The Memory of Autumn Leaves." As of January 2026, there are no records of resale, exhibitions, or further public appearances, suggesting it remains in private ownership. It continues to be referenced as one of the most expensive blue diamonds ever sold, underscoring the growing investment appeal of fancy colored diamonds.
History of the Artemis Pink Diamond
The Artemis Pink diamond is a 16-carat, pear-shaped, Fancy Intense Pink diamond, graded as VVS1 clarity by the GIA. Pink diamonds derive their color from structural distortions in the crystal lattice rather than impurities, making them exceptionally rare.
Origin and Mining
While over 90% of natural pink diamonds originate from Australia's Argyle Mine in Western Australia, which closed in 2020, some reports indicate the Artemis Pink was mined in South Africa. Pink diamonds have also been found in Brazil, Russia, Tanzania, and occasionally South Africa, though the latter is uncommon. The exact mine and discovery date are not publicly known, but geological studies suggest pink diamonds formed around 1.3 billion years ago during the breakup of the supercontinent Nuna.
Pre-Auction History
Similar to the Apollo Blue, the Artemis Pink's early history—including rough extraction, polishing, and ownership—is not detailed in available records. It was matched with the Apollo Blue by Sotheby's for the auction, mounted as an earring, and named after the Greek goddess Artemis to symbolize its ethereal beauty and rarity. It likely came from a private consignor with no prior public sales noted.
2017 Auction and Sale
At the same Sotheby's Geneva auction on May 16, 2017, the Artemis Pink sold for $15.334 million (CHF 15,120,750, including buyer's premium). The same anonymous buyer acquired it, making the pair the most expensive earrings ever sold at auction (totaling $57.4 million), though they were auctioned as separate lots.
Post-Auction Ownership and Current Status
The buyer renamed it "The Dream of Autumn Leaves" shortly after the purchase. No subsequent sales or public displays have been reported as of January 2026, indicating it stays in the same private collection. The diamond is often cited alongside its blue counterpart as a benchmark for fancy colored diamond values.Both diamonds' histories are notably private prior to 2017, with their fame stemming primarily from the record-breaking auction. They exemplify the market's enthusiasm for rare colored diamonds, driven by their scarcity and aesthetic appeal.
The breathtaking Apollo and Artemis #Diamonds lead our Magnificent Jewels & Noble Jewels sale in #Geneva this spring https://t.co/uJ1tcXugGg pic.twitter.com/hW0pbkPf7D
— Sotheby's (@Sothebys) April 10, 2017
Cullinan Mine from 2014
Intro
The raw gems of the Blue Moon and of the Cullinan Dream were found respectively in January and June 2014 at the Cullinan mine. Is there a special prospection campaign or a mere coincidence?
The discoveries of the 29.6-carat blue rough (later the Blue Moon) in January 2014 and the 122.52-carat blue rough (later the Cullinan Dream) in June 2014 at Petra Diamonds' Cullinan mine appear to be a mere coincidence rather than the result of a targeted prospection campaign for blue diamonds. The Cullinan mine, renowned as the world's primary source of rare Type IIb blue diamonds, was undergoing its ongoing C-Cut expansion project during this period—a multi-year development initiative started around 2012 to deepen the shaft, access new ore blocks, and increase overall production capacity from about 1 million carats per year to over 2.6 million by FY2019. This expansion involved standard block cave mining methods to tap into deeper kimberlite resources known for yielding large and high-quality gems, including blues, but contemporary reports and Petra's announcements describe the 2014 finds as individual "exceptional" recoveries during routine operations, without reference to any specialized blue diamond-focused exploration or prospection efforts.
Petra's heritage and operational updates highlight Cullinan's history of sporadic large blue diamond finds (e.g., a 25.5-carat blue in 2013 and later clusters like five blues in September 2020), attributing them to the mine's unique geology rather than deliberate campaigns. The 2014 discoveries occurred amid increased mining activity from the expansion, which naturally boosted the chances of encountering rare stones, but they were not linked to any specific blue-targeted initiative in available records or reports. Blue diamonds form due to boron impurities in the kimberlite and are unevenly distributed, making their appearance unpredictable even in a prolific source like Cullinan.
The discoveries of the 29.6-carat blue rough (later the Blue Moon) in January 2014 and the 122.52-carat blue rough (later the Cullinan Dream) in June 2014 at Petra Diamonds' Cullinan mine appear to be a mere coincidence rather than the result of a targeted prospection campaign for blue diamonds. The Cullinan mine, renowned as the world's primary source of rare Type IIb blue diamonds, was undergoing its ongoing C-Cut expansion project during this period—a multi-year development initiative started around 2012 to deepen the shaft, access new ore blocks, and increase overall production capacity from about 1 million carats per year to over 2.6 million by FY2019. This expansion involved standard block cave mining methods to tap into deeper kimberlite resources known for yielding large and high-quality gems, including blues, but contemporary reports and Petra's announcements describe the 2014 finds as individual "exceptional" recoveries during routine operations, without reference to any specialized blue diamond-focused exploration or prospection efforts.
Petra's heritage and operational updates highlight Cullinan's history of sporadic large blue diamond finds (e.g., a 25.5-carat blue in 2013 and later clusters like five blues in September 2020), attributing them to the mine's unique geology rather than deliberate campaigns. The 2014 discoveries occurred amid increased mining activity from the expansion, which naturally boosted the chances of encountering rare stones, but they were not linked to any specific blue-targeted initiative in available records or reports. Blue diamonds form due to boron impurities in the kimberlite and are unevenly distributed, making their appearance unpredictable even in a prolific source like Cullinan.
5️⃣ The Cullinan Dream
— Hewnfromstone (@Hewnfromstone1) September 8, 2025
24.18 carats. Sold for $25.4M in 2016. Proof that when size meets rarity, collectors pay insane sums. pic.twitter.com/DGLmhaP6al
1
2014 The Blue Moon of Josephine by Cora International
2015 SOLD for CHF 49M by Sotheby's
The ground continues to unearth important diamonds. Yet, the discovery announced by Petra Diamonds in January 2014 of a 29.62 carat blue gem from the much famous Cullinan mine in South Africa aroused a particular interest in the diamond community.
The new diamond is fancy vivid blue without inclusion, which is already a great rarity. It was purchased by Cora International, headquartered in New York, which processed it. This fancy vivid blue cut to 12.03 carats is the largest internally flawless blue diamond in cushion shape.
Once completed, it revealed even more exceptional qualities. Its ocean blue color is perfect without a secondary hue. It has no fluorescence. An exposure to ultraviolet radiation generates an intense orange-red phosphorescence that persists for about twenty seconds, a sensational feature which is known only to a few blue diamonds of absolute purity.
It is a masterpiece in both its size and features. It was named The Blue Moon in reference both to its shape and to the saying 'Once in a blue moon' that means a total rarity. It seems inconceivable to find better in its class, especially since the production of the Cullinan mine tends to decrease.
The Blue Moon was sold for CHF 49M from a lower estimate of US $ 35M by Sotheby's on November 11, 2015, lot 513. Please watch the video shared by Sotheby's. Its record value at US $ 4M per carat rewards its absolute purity generating the phosphorescence effect.
It is now referred as the Blue Moon of Josephine.
Blue Moon : One of the first major blue diamonds post-discovery to achieve flawless clarity. Provide details about that breakthrough.
Discovery and Acquisition
The Blue Moon of Josephine, originally known as the Blue Moon diamond, was discovered in January 2014 at the Cullinan Mine in South Africa. This historic mine, famous for producing rare blue diamonds, yielded a 29.62-carat rough stone that exhibited promising blue hues due to trace boron impurities. Shortly after, it was acquired by Cora International LLC, a New York-based diamond manufacturer, for $25.6 million—setting a record price per carat for a rough diamond at the time.
Examination Process
Before cutting, the rough diamond underwent extensive scientific examination to assess its potential. This included infrared (IR) spectroscopy conducted at the Smithsonian Institution's Department of Mineral Sciences using advanced equipment like the Thermo Scientific Nicolet 6700 FTIR spectrometer. The analysis confirmed it as a Type IIb diamond, with no detectable nitrogen and an uncompensated boron concentration of approximately 0.26 ± 0.04 ppm, responsible for its blue color. Additional tests revealed intense orange-red phosphorescence under short-wave UV light, lasting up to 20 seconds, with spectral peaks at 660 nm (dominant) and 500 nm. Birefringence imaging under crossed polarizers showed a "tatami" strain pattern with gray and blue interference colors, indicating internal stresses typical of such gems. No fluorescence was observed. These months-long studies, spanning from discovery to June 2014, were crucial for planning the cut to maximize color, size, and clarity while minimizing risks. Cutting and Polishing
The cutting process, handled by Cora International in New York, took about six months and transformed the rough into a 12.03-carat cushion modified brilliant cut diamond (measuring 15.57 × 13.47 × 7.55 mm). This involved precise faceting to enhance brilliance and light return, incorporating a small culet facet to aid in flaw removal. The Gemological Institute of America (GIA) graded it as Fancy Vivid Blue (the highest color saturation for blues) and Internally Flawless (IF), meaning no internal inclusions visible under 10x magnification.
The Breakthrough in Achieving Flawless Clarity
Achieving Internally Flawless clarity in the Blue Moon was a significant breakthrough because Type IIb blue diamonds, colored by boron, often feature structural weaknesses, inclusions, or uneven color distribution that make high-clarity cuts exceedingly difficult—especially in stones over 10 carats. Boron impurities can introduce defects that compromise the crystal lattice, leading to internal flaws that are hard to eliminate without sacrificing size or color intensity. Prior to this, large Fancy Vivid Blue diamonds rarely achieved IF clarity post-discovery, as the cutting process risked amplifying these issues or reducing the stone too much. The team at Cora International overcame these challenges through advanced examination techniques (like detailed spectroscopy and strain analysis) to map inclusions precisely, followed by skilled, risk-calculated faceting that removed imperfections while preserving the vivid hue and yielding a substantial 12.03-carat gem. This marked one of the first instances of a major blue diamond being cut to such perfection shortly after discovery, setting a new benchmark in gemology and contributing to its record-breaking auction sale in 2015.
The new diamond is fancy vivid blue without inclusion, which is already a great rarity. It was purchased by Cora International, headquartered in New York, which processed it. This fancy vivid blue cut to 12.03 carats is the largest internally flawless blue diamond in cushion shape.
Once completed, it revealed even more exceptional qualities. Its ocean blue color is perfect without a secondary hue. It has no fluorescence. An exposure to ultraviolet radiation generates an intense orange-red phosphorescence that persists for about twenty seconds, a sensational feature which is known only to a few blue diamonds of absolute purity.
It is a masterpiece in both its size and features. It was named The Blue Moon in reference both to its shape and to the saying 'Once in a blue moon' that means a total rarity. It seems inconceivable to find better in its class, especially since the production of the Cullinan mine tends to decrease.
The Blue Moon was sold for CHF 49M from a lower estimate of US $ 35M by Sotheby's on November 11, 2015, lot 513. Please watch the video shared by Sotheby's. Its record value at US $ 4M per carat rewards its absolute purity generating the phosphorescence effect.
It is now referred as the Blue Moon of Josephine.
Blue Moon : One of the first major blue diamonds post-discovery to achieve flawless clarity. Provide details about that breakthrough.
Discovery and Acquisition
The Blue Moon of Josephine, originally known as the Blue Moon diamond, was discovered in January 2014 at the Cullinan Mine in South Africa. This historic mine, famous for producing rare blue diamonds, yielded a 29.62-carat rough stone that exhibited promising blue hues due to trace boron impurities. Shortly after, it was acquired by Cora International LLC, a New York-based diamond manufacturer, for $25.6 million—setting a record price per carat for a rough diamond at the time.
Examination Process
Before cutting, the rough diamond underwent extensive scientific examination to assess its potential. This included infrared (IR) spectroscopy conducted at the Smithsonian Institution's Department of Mineral Sciences using advanced equipment like the Thermo Scientific Nicolet 6700 FTIR spectrometer. The analysis confirmed it as a Type IIb diamond, with no detectable nitrogen and an uncompensated boron concentration of approximately 0.26 ± 0.04 ppm, responsible for its blue color. Additional tests revealed intense orange-red phosphorescence under short-wave UV light, lasting up to 20 seconds, with spectral peaks at 660 nm (dominant) and 500 nm. Birefringence imaging under crossed polarizers showed a "tatami" strain pattern with gray and blue interference colors, indicating internal stresses typical of such gems. No fluorescence was observed. These months-long studies, spanning from discovery to June 2014, were crucial for planning the cut to maximize color, size, and clarity while minimizing risks. Cutting and Polishing
The cutting process, handled by Cora International in New York, took about six months and transformed the rough into a 12.03-carat cushion modified brilliant cut diamond (measuring 15.57 × 13.47 × 7.55 mm). This involved precise faceting to enhance brilliance and light return, incorporating a small culet facet to aid in flaw removal. The Gemological Institute of America (GIA) graded it as Fancy Vivid Blue (the highest color saturation for blues) and Internally Flawless (IF), meaning no internal inclusions visible under 10x magnification.
The Breakthrough in Achieving Flawless Clarity
Achieving Internally Flawless clarity in the Blue Moon was a significant breakthrough because Type IIb blue diamonds, colored by boron, often feature structural weaknesses, inclusions, or uneven color distribution that make high-clarity cuts exceedingly difficult—especially in stones over 10 carats. Boron impurities can introduce defects that compromise the crystal lattice, leading to internal flaws that are hard to eliminate without sacrificing size or color intensity. Prior to this, large Fancy Vivid Blue diamonds rarely achieved IF clarity post-discovery, as the cutting process risked amplifying these issues or reducing the stone too much. The team at Cora International overcame these challenges through advanced examination techniques (like detailed spectroscopy and strain analysis) to map inclusions precisely, followed by skilled, risk-calculated faceting that removed imperfections while preserving the vivid hue and yielding a substantial 12.03-carat gem. This marked one of the first instances of a major blue diamond being cut to such perfection shortly after discovery, setting a new benchmark in gemology and contributing to its record-breaking auction sale in 2015.
The price of natural diamonds has been hit by the surge in demand for lab diamonds, but rare and historic natural diamonds, stll command super high prices. The Blue Moon diamond that originated in South Africa is a good example. Also known as the Blue Moon Of Josephine diamond. pic.twitter.com/NaLOHj6rUh
— Kaisilver (@jewelrythailand) March 8, 2025
2
2014 The Cullinan Dream (fancy intense)
2016 SOLD for $ 25.4M by Christie's
The Cullinan mine now owned by Petra Diamonds still remains the most regular purveyor of type IIb color diamonds, 10 to 20 times rarer than the IIa.
An extraordinary fancy intense blue gem weighing 122.52 carats was discovered at Cullinan in June 2014. The jewelers mapped with accuracy its internal crystalline regularity by using the semiconductor characteristics that are specific to the type IIb diamonds.
This non-destructive analysis enabled to optimize the cut. Four diamonds were produced. The Cullinan Dream is the biggest of the four. It is rectangular with cut corners and weighs 24.18 carats. Its clarity is VS2. It was sold for $ 25.4M by Christie's on June 9, 2016, lot 261.
This diamond is exceptional. Its fancy intense hue is much rarer than the fancy vivid blue. The Oppenheimer Blue, identified as the largest fancy vivid blue ever offered at auction, only weighed 14.62 carats. It was sold for CHF 57M by Christie's in 2016.
Its price of $ 1M per carat is consistent with results obtained on other blue diamonds. A fancy intense blue with a VVS2 clarity weighing 7.64 carats was sold for CHF 9M by Sotheby's on 11 May 2010.
The other highly rare variety of blue, the fancy deep blue, can reach a price per carat of the same level or even higher. The estimate by Sotheby's in April 2016 at $ 2.6M per carat for the diamond of Shirley Temple was nevertheless much exaggerated.
Full history of the Cullinan Dream diamond
The Cullinan Dream is a 24.18-carat fancy intense blue diamond, notable for its rarity as a Type IIb stone and its origin from South Africa's historic Cullinan mine. This mine, discovered in 1902 and originally known as the Premier Mine, gained global fame in 1905 with the unearthing of the 3,106.75-carat Cullinan rough—the largest gem-quality diamond ever found—which was later cut into multiple stones, including the Cullinan I (Star of Africa) and Cullinan II, now part of the British Crown Jewels. The mine has since produced other legendary diamonds, such as the 755-carat Golden Jubilee, the 599-carat De Beers Centenary, and the 507-carat Cullinan Heritage in 2009. Acquired by Petra Diamonds from De Beers in 2008, it remains the world's primary source of blue diamonds.
In June 2014, Petra Diamonds discovered a 122.52-carat blue rough diamond at the Cullinan mine. This exceptional Type IIb rough—characterized by boron impurities that impart its blue hue and electrical conductivity—was sold later that year for $23.5 million to an unnamed cutting and polishing partnership, with Petra retaining a 15% interest in the proceeds from the eventual sale of the polished stones (minus expenses).
A master gem cutter (identity not publicly disclosed) polished the rough into four blue diamonds: a 7.00-carat cushion-cut, a 10.30-carat radiant-cut, an 11.30-carat pear-shaped, and the 24.18-carat cut-cornered rectangular mixed-cut that became the Cullinan Dream. The largest of these, the Cullinan Dream, was graded by the Gemological Institute of America (GIA) on February 26, 2016, as fancy intense blue color, VS2 clarity, with natural color distribution and no indications of treatment. As a Type IIb diamond, it belongs to an ultra-rare category (less than 0.5% of natural diamonds), often lacking the symmetrical crystal forms of more common Type Ia diamonds and exhibiting semi-conductive properties that influence cutting decisions for optimal color saturation. It was mounted in a platinum ring flanked by two tapered baguette-cut white diamonds totaling about 2.36 carats. The name "Cullinan Dream" reflects its "captivating and celestial beauty," evoking the mine's legacy while highlighting its ethereal blue tone.
On June 9, 2016, the Cullinan Dream was offered at Christie's Magnificent Jewels auction in New York, with a pre-sale estimate of $23 million to $29 million. It sold for $25.365 million to an anonymous buyer, setting auction records as the largest and most expensive fancy intense blue diamond ever sold. This price per carat equated to about $1.05 million, underscoring the premium for its size, intensity, and provenance. The sale was part of a vibrant 2016 auction season for colored diamonds, though it fell short of records set by vivid blue stones like the Oppenheimer Blue, which fetched $57.5 million earlier that year.
Since the 2016 auction, the Cullinan Dream has remained in private ownership, with no public records of resale, exhibition, or further provenance details available as of 2026. It continues to be referenced in lists of the world's most valuable blue diamonds, often ranking among the top 10 by price due to its historical significance and rarity.
An extraordinary fancy intense blue gem weighing 122.52 carats was discovered at Cullinan in June 2014. The jewelers mapped with accuracy its internal crystalline regularity by using the semiconductor characteristics that are specific to the type IIb diamonds.
This non-destructive analysis enabled to optimize the cut. Four diamonds were produced. The Cullinan Dream is the biggest of the four. It is rectangular with cut corners and weighs 24.18 carats. Its clarity is VS2. It was sold for $ 25.4M by Christie's on June 9, 2016, lot 261.
This diamond is exceptional. Its fancy intense hue is much rarer than the fancy vivid blue. The Oppenheimer Blue, identified as the largest fancy vivid blue ever offered at auction, only weighed 14.62 carats. It was sold for CHF 57M by Christie's in 2016.
Its price of $ 1M per carat is consistent with results obtained on other blue diamonds. A fancy intense blue with a VVS2 clarity weighing 7.64 carats was sold for CHF 9M by Sotheby's on 11 May 2010.
The other highly rare variety of blue, the fancy deep blue, can reach a price per carat of the same level or even higher. The estimate by Sotheby's in April 2016 at $ 2.6M per carat for the diamond of Shirley Temple was nevertheless much exaggerated.
Full history of the Cullinan Dream diamond
The Cullinan Dream is a 24.18-carat fancy intense blue diamond, notable for its rarity as a Type IIb stone and its origin from South Africa's historic Cullinan mine. This mine, discovered in 1902 and originally known as the Premier Mine, gained global fame in 1905 with the unearthing of the 3,106.75-carat Cullinan rough—the largest gem-quality diamond ever found—which was later cut into multiple stones, including the Cullinan I (Star of Africa) and Cullinan II, now part of the British Crown Jewels. The mine has since produced other legendary diamonds, such as the 755-carat Golden Jubilee, the 599-carat De Beers Centenary, and the 507-carat Cullinan Heritage in 2009. Acquired by Petra Diamonds from De Beers in 2008, it remains the world's primary source of blue diamonds.
In June 2014, Petra Diamonds discovered a 122.52-carat blue rough diamond at the Cullinan mine. This exceptional Type IIb rough—characterized by boron impurities that impart its blue hue and electrical conductivity—was sold later that year for $23.5 million to an unnamed cutting and polishing partnership, with Petra retaining a 15% interest in the proceeds from the eventual sale of the polished stones (minus expenses).
A master gem cutter (identity not publicly disclosed) polished the rough into four blue diamonds: a 7.00-carat cushion-cut, a 10.30-carat radiant-cut, an 11.30-carat pear-shaped, and the 24.18-carat cut-cornered rectangular mixed-cut that became the Cullinan Dream. The largest of these, the Cullinan Dream, was graded by the Gemological Institute of America (GIA) on February 26, 2016, as fancy intense blue color, VS2 clarity, with natural color distribution and no indications of treatment. As a Type IIb diamond, it belongs to an ultra-rare category (less than 0.5% of natural diamonds), often lacking the symmetrical crystal forms of more common Type Ia diamonds and exhibiting semi-conductive properties that influence cutting decisions for optimal color saturation. It was mounted in a platinum ring flanked by two tapered baguette-cut white diamonds totaling about 2.36 carats. The name "Cullinan Dream" reflects its "captivating and celestial beauty," evoking the mine's legacy while highlighting its ethereal blue tone.
On June 9, 2016, the Cullinan Dream was offered at Christie's Magnificent Jewels auction in New York, with a pre-sale estimate of $23 million to $29 million. It sold for $25.365 million to an anonymous buyer, setting auction records as the largest and most expensive fancy intense blue diamond ever sold. This price per carat equated to about $1.05 million, underscoring the premium for its size, intensity, and provenance. The sale was part of a vibrant 2016 auction season for colored diamonds, though it fell short of records set by vivid blue stones like the Oppenheimer Blue, which fetched $57.5 million earlier that year.
Since the 2016 auction, the Cullinan Dream has remained in private ownership, with no public records of resale, exhibition, or further provenance details available as of 2026. It continues to be referenced in lists of the world's most valuable blue diamonds, often ranking among the top 10 by price due to its historical significance and rarity.
3
2020-2021 The Infinite Blue
2023 SOLD for HK$ 200M by Sotheby's
The Infinite Blue is a radiant cut fancy vivid blue diamond weighing 11.28 carats in a VS2 clarity. Its raw gem had been found in the same Cullinan mine as the Blue Moon of Josephine, the phosphorescent internally flawless fancy vivid blue sold for CHF 49M by Sotheby's in 2015.
The Infinite Blue is surrounded by pink tint brilliant diamonds and shouldered by white trapeze diamonds on a 18 karat white and pink gold ring. It was sold for HK $ 200M by Sotheby's on October 5, 2023, lot 8001. Please watch the video shared by the auction house.
History of the Infinite Blue diamond, sold in 2023 by Sotheby's
Origin and Discovery
The Infinite Blue diamond originates from the Cullinan Mine in South Africa, renowned for producing some of the world's most exceptional diamonds, including rare blue ones. It was part of the Letlapa Tala Collection ("blue rock" in Northern Sotho), a set of five rough blue diamonds discovered by Petra Diamonds around 2020-2021. The collection included rough stones ranging from 9.61 to 25.75 carats, with the Infinite Blue being cut from the largest of these. Blue diamonds like this form deeper in the Earth's mantle—around 400 miles below the surface—due to trace amounts of boron incorporating into the crystal structure, which imparts their distinctive color. The Cullinan Mine has a storied history, having yielded famous gems such as the 530-carat Cullinan I (Great Star of Africa) and other notable blues like the Blue Moon of Josephine. Only three Fancy Vivid Blue diamonds over 10 carats from this mine have ever appeared at auction prior to the Infinite Blue.
Cutting and Characteristics
The rough stone was expertly cut and polished into an 11.28-carat radiant-cut diamond with a cut-cornered rectangular mixed cut, blending elements of an emerald cut outline with kite-shaped facets for enhanced brilliance. This specific carat weight was intentionally chosen to incorporate the number 8, symbolizing prosperity in Asian cultures and infinity. Graded by the Gemological Institute of America (GIA) on June 14, 2023, it received a Fancy Vivid Blue color grade (the highest saturation for blues, representing the top 1% of evaluated blue diamonds), Natural Colour, VS2 clarity, and Type IIb classification—a rare category making up less than 0.5% of all diamonds. The diamond exhibits an azure hue reminiscent of the ocean and exceptional light performance. It was set in a ring mounting featuring a halo of natural pink diamonds and trapezoid-cut white diamonds on each side.
Auction and Sale
Unveiled at a private event in New York City, the Infinite Blue was offered by Sotheby's in a dedicated single-lot live auction in Hong Kong on October 5, 2023. Estimated to fetch between $26 million and $37 million, it ultimately sold for approximately $25.3 million (HK$200 million including buyer's premium), falling slightly short of expectations after competitive bidding. This sale placed it among elite blue diamonds, though below records set by peers like The De Beers Blue ($57.5 million in 2022). No details on previous private ownership are publicly available, suggesting it was brought to market shortly after cutting and grading.
Compare to Blue Moon of Josephine
Overview
The Infinite Blue and the Blue Moon of Josephine are both exceptional Fancy Vivid Blue diamonds originating from the Cullinan Mine in South Africa, known for producing some of the rarest blue gems. While they share similarities in color intensity and rarity (both Type IIb diamonds, representing less than 0.5% of all diamonds), they differ in size, clarity, cut, and auction performance. The Blue Moon of Josephine set a per-carat record in 2015, while the Infinite Blue, sold more recently in 2023, fetched a lower price amid market conditions.
Below is a detailed comparison.
Carat Weight
Infinite : 11.28 carats
Moon : 12.03 carats
Color Grade
Infinite : Fancy Vivid Blue (highest saturation, top 1% of blue diamonds)
Moon : Fancy Vivid Blue
Clarity Grade
Infinite : VS2
Moon : Internally Flawless (IF)
Cut
Infinite : Radiant-cut (cut-cornered rectangular mixed cut with kite-shaped facets for brilliance)
Moon : Cushion cut (modified brilliant for optimal light return)
Origin
both : Cullinan Mine, South Africa
Discovery Year
Infinite : Around 2020-2021 (part of Letlapa Tala Collection)
Moon : January 2014
Rough Weight
Infinite : From a 25.75-carat rough (largest in collection)
Moon : 29.62 carats
Auction House
both : Sotheby's
Sale Location
Infonote : Hong Kong
Moon : Geneva
Sale Date
Infinite : October 5, 2023
Moon : November 11, 2015
Sale Price
Infinite : $25.3 million (HK$200 million including premium; below estimate of $26-37 million)
Moon : $48.4 million (record per-carat at $4 million; including premium)
Buyer
Infinite : Anonymous
Moon : Joseph Lau (Hong Kong billionaire; renamed after his daughter Josephine)
Notable Features
Infinite : Set in a ring with pink and white diamond halo; carat weight includes "8" for cultural symbolism
Moon : One of the first major blue diamonds post-discovery to achieve flawless clarity; set a benchmark for blue diamond auctions
Rarity Context
Infinite : One of only three Fancy Vivid Blue diamonds over 10 carats from Cullinan at auction before it
Moon : Extremely rare; blue diamonds comprise ~0.1% of output from Cullinan
Key Differences and Similarities
Both diamonds owe their vivid blue hue to boron impurities formed deep in the Earth's mantle, making them highly sought after. The Blue Moon of Josephine commands a higher price due to its superior clarity (IF vs. VS2), slightly larger size, and historical significance as a record-setter in 2015, when blue diamond demand was peaking. In contrast, the Infinite Blue's radiant cut enhances brilliance in a modern style, but its sale reflected a softer market for colored diamonds in 2023. Despite the price gap, both rank among the top blue diamonds ever auctioned, with the Blue Moon still holding a stronger legacy in per-carat value.
The Infinite Blue is surrounded by pink tint brilliant diamonds and shouldered by white trapeze diamonds on a 18 karat white and pink gold ring. It was sold for HK $ 200M by Sotheby's on October 5, 2023, lot 8001. Please watch the video shared by the auction house.
History of the Infinite Blue diamond, sold in 2023 by Sotheby's
Origin and Discovery
The Infinite Blue diamond originates from the Cullinan Mine in South Africa, renowned for producing some of the world's most exceptional diamonds, including rare blue ones. It was part of the Letlapa Tala Collection ("blue rock" in Northern Sotho), a set of five rough blue diamonds discovered by Petra Diamonds around 2020-2021. The collection included rough stones ranging from 9.61 to 25.75 carats, with the Infinite Blue being cut from the largest of these. Blue diamonds like this form deeper in the Earth's mantle—around 400 miles below the surface—due to trace amounts of boron incorporating into the crystal structure, which imparts their distinctive color. The Cullinan Mine has a storied history, having yielded famous gems such as the 530-carat Cullinan I (Great Star of Africa) and other notable blues like the Blue Moon of Josephine. Only three Fancy Vivid Blue diamonds over 10 carats from this mine have ever appeared at auction prior to the Infinite Blue.
Cutting and Characteristics
The rough stone was expertly cut and polished into an 11.28-carat radiant-cut diamond with a cut-cornered rectangular mixed cut, blending elements of an emerald cut outline with kite-shaped facets for enhanced brilliance. This specific carat weight was intentionally chosen to incorporate the number 8, symbolizing prosperity in Asian cultures and infinity. Graded by the Gemological Institute of America (GIA) on June 14, 2023, it received a Fancy Vivid Blue color grade (the highest saturation for blues, representing the top 1% of evaluated blue diamonds), Natural Colour, VS2 clarity, and Type IIb classification—a rare category making up less than 0.5% of all diamonds. The diamond exhibits an azure hue reminiscent of the ocean and exceptional light performance. It was set in a ring mounting featuring a halo of natural pink diamonds and trapezoid-cut white diamonds on each side.
Auction and Sale
Unveiled at a private event in New York City, the Infinite Blue was offered by Sotheby's in a dedicated single-lot live auction in Hong Kong on October 5, 2023. Estimated to fetch between $26 million and $37 million, it ultimately sold for approximately $25.3 million (HK$200 million including buyer's premium), falling slightly short of expectations after competitive bidding. This sale placed it among elite blue diamonds, though below records set by peers like The De Beers Blue ($57.5 million in 2022). No details on previous private ownership are publicly available, suggesting it was brought to market shortly after cutting and grading.
Compare to Blue Moon of Josephine
Overview
The Infinite Blue and the Blue Moon of Josephine are both exceptional Fancy Vivid Blue diamonds originating from the Cullinan Mine in South Africa, known for producing some of the rarest blue gems. While they share similarities in color intensity and rarity (both Type IIb diamonds, representing less than 0.5% of all diamonds), they differ in size, clarity, cut, and auction performance. The Blue Moon of Josephine set a per-carat record in 2015, while the Infinite Blue, sold more recently in 2023, fetched a lower price amid market conditions.
Below is a detailed comparison.
Carat Weight
Infinite : 11.28 carats
Moon : 12.03 carats
Color Grade
Infinite : Fancy Vivid Blue (highest saturation, top 1% of blue diamonds)
Moon : Fancy Vivid Blue
Clarity Grade
Infinite : VS2
Moon : Internally Flawless (IF)
Cut
Infinite : Radiant-cut (cut-cornered rectangular mixed cut with kite-shaped facets for brilliance)
Moon : Cushion cut (modified brilliant for optimal light return)
Origin
both : Cullinan Mine, South Africa
Discovery Year
Infinite : Around 2020-2021 (part of Letlapa Tala Collection)
Moon : January 2014
Rough Weight
Infinite : From a 25.75-carat rough (largest in collection)
Moon : 29.62 carats
Auction House
both : Sotheby's
Sale Location
Infonote : Hong Kong
Moon : Geneva
Sale Date
Infinite : October 5, 2023
Moon : November 11, 2015
Sale Price
Infinite : $25.3 million (HK$200 million including premium; below estimate of $26-37 million)
Moon : $48.4 million (record per-carat at $4 million; including premium)
Buyer
Infinite : Anonymous
Moon : Joseph Lau (Hong Kong billionaire; renamed after his daughter Josephine)
Notable Features
Infinite : Set in a ring with pink and white diamond halo; carat weight includes "8" for cultural symbolism
Moon : One of the first major blue diamonds post-discovery to achieve flawless clarity; set a benchmark for blue diamond auctions
Rarity Context
Infinite : One of only three Fancy Vivid Blue diamonds over 10 carats from Cullinan at auction before it
Moon : Extremely rare; blue diamonds comprise ~0.1% of output from Cullinan
Key Differences and Similarities
Both diamonds owe their vivid blue hue to boron impurities formed deep in the Earth's mantle, making them highly sought after. The Blue Moon of Josephine commands a higher price due to its superior clarity (IF vs. VS2), slightly larger size, and historical significance as a record-setter in 2015, when blue diamond demand was peaking. In contrast, the Infinite Blue's radiant cut enhances brilliance in a modern style, but its sale reflected a softer market for colored diamonds in 2023. Despite the price gap, both rank among the top blue diamonds ever auctioned, with the Blue Moon still holding a stronger legacy in per-carat value.
This blue rock sold for US $25.4 Million!
— Reena Ahluwalia (@reenaahluwalia) October 5, 2023
The Infinite Blue Diamond.
Fancy Vivid Blue Diamond, 11.28 carats, Type IIb.
Congrats, @Sothebys Hong Kong. pic.twitter.com/hnxnMPTjpk
4
2021 The De Beers Cullinan Blue by Diacore
2022 SOLD for HK$ 450M by Sotheby's
The De Beers Blue, a fancy vivid blue weighing 15.10 carats, is the largest vivid blue made available at auction and the largest internally flawless step cut diamond graded by the GIA. Its stone of about 40 carats has been extracted in 2021 by De Beers in their Cullinan mine.
It is bigger and clearer than the rectangular cut VVS1 14.62 carat Oppenheimer Blue, sold for CHF 57M by Christie's on May 18, 2016. It has the same internally flawless clarity as the cushion cut 12.03 carats of the Blue Moon, remarkable for its 20 second phosphorescent effect after exposure to UV light, sold for CHF 49M by Sotheby's on November 11, 2015.
The step cut, rectangular cut and emerald cut are the best suited to display the perfection of the gem, revealing any defect without pity and displaying the color in its evenly saturated beauty while optimizing the light reflection.
This masterwork of nature and craftsmanship was sold for HK$ 450M by Sotheby's in Hong Kong on April 27, 2022, lot 1800. Its $3.8 million per-carat value, surpassing the prior benchmark set by the 2015 Oppenheimer Blue, is driven by boron impurities that tint only 0.02% of diamonds blue.
The De Beers Cullinan Blue diamond, a rare Type IIb fancy vivid blue gem, has a relatively short but notable history tied to one of the world's most famous diamond mines.
Discovery and Mining
The diamond originated from a 39.34-carat rough stone unearthed in April 2021 at the Cullinan Mine in South Africa, operated by Petra Diamonds. The Cullinan Mine, discovered in 1902 and named after its founder Thomas Cullinan, has a storied past as the source of the world's largest rough diamond ever found—the 3,106-carat Cullinan Diamond in 1905, which was later cut into pieces for the British Crown Jewels. The mine is one of the few global sources for blue diamonds, which form due to trace amounts of boron in their crystal structure, and has produced other notable blues over the decades. Petra Diamonds, which acquired the mine from De Beers in 2008, certified this rough as conflict-free under the Kimberley Process.
Acquisition and Cutting
Shortly after discovery, the rough was acquired by a partnership between De Beers Group and master diamond manufacturer Diacore for an undisclosed sum (reported in some sources as around $40 million). Diacore, known for handling exceptional stones, spent nearly a year meticulously studying, cutting, and polishing the rough into a 15.10-carat step-cut rectangular diamond. This process involved significant risk due to the stone's rarity and value, with the final polish emphasizing its intense color and clarity. The Gemological Institute of America (GIA) graded it as Fancy Vivid Blue (the highest color grade for blues, given to less than 1% of submissions), Internally Flawless, and Type IIb—making it the largest such step-cut vivid blue ever graded by the GIA and the largest vivid blue to appear at auction.
Auction and Sale
Named the De Beers Cullinan Blue in honor of its mine and the De Beers collaboration, the diamond was unveiled in February 2022 and toured globally (including stops in New York, London, Dubai, and Asia) before its standalone auction at Sotheby's Magnificent Jewels sale in Hong Kong on April 27, 2022. Estimated at over $48 million, it sold after intense bidding for HK$450,925,000 (approximately US$57.47 million) to an anonymous private collector via telephone. This set a new record for the highest price per carat for a blue diamond at about $3.8 million, surpassing the previous benchmark held by the 12.03-carat Blue Moon of Josephine (sold for $48.5 million in 2015). It fell just short of the overall record for a vivid blue diamond, held by the 14.62-carat Oppenheimer Blue ($57.54 million in 2016).
Post-Sale History and Controversies
Since the 2022 sale, there have been no public updates on the diamond's ownership, resale, or current location as of January 2026—it remains in private hands with no reported exhibitions or further auctions. The diamond's history is not without ethical scrutiny: While certified conflict-free, its association with De Beers has drawn criticism due to the company's historical role in South Africa's diamond industry during apartheid, including labor exploitation and market monopolization. However, the Cullinan Mine's modern operations under Petra emphasize sustainable practices, and blue diamonds like this one represent less than 0.01% of global production, underscoring their geological rarity.
This diamond exemplifies the enduring allure of blue gems, with historical parallels to famous blues like the Hope Diamond (cut from the 17th-century Tavernier Blue).
It is bigger and clearer than the rectangular cut VVS1 14.62 carat Oppenheimer Blue, sold for CHF 57M by Christie's on May 18, 2016. It has the same internally flawless clarity as the cushion cut 12.03 carats of the Blue Moon, remarkable for its 20 second phosphorescent effect after exposure to UV light, sold for CHF 49M by Sotheby's on November 11, 2015.
The step cut, rectangular cut and emerald cut are the best suited to display the perfection of the gem, revealing any defect without pity and displaying the color in its evenly saturated beauty while optimizing the light reflection.
This masterwork of nature and craftsmanship was sold for HK$ 450M by Sotheby's in Hong Kong on April 27, 2022, lot 1800. Its $3.8 million per-carat value, surpassing the prior benchmark set by the 2015 Oppenheimer Blue, is driven by boron impurities that tint only 0.02% of diamonds blue.
The De Beers Cullinan Blue diamond, a rare Type IIb fancy vivid blue gem, has a relatively short but notable history tied to one of the world's most famous diamond mines.
Discovery and Mining
The diamond originated from a 39.34-carat rough stone unearthed in April 2021 at the Cullinan Mine in South Africa, operated by Petra Diamonds. The Cullinan Mine, discovered in 1902 and named after its founder Thomas Cullinan, has a storied past as the source of the world's largest rough diamond ever found—the 3,106-carat Cullinan Diamond in 1905, which was later cut into pieces for the British Crown Jewels. The mine is one of the few global sources for blue diamonds, which form due to trace amounts of boron in their crystal structure, and has produced other notable blues over the decades. Petra Diamonds, which acquired the mine from De Beers in 2008, certified this rough as conflict-free under the Kimberley Process.
Acquisition and Cutting
Shortly after discovery, the rough was acquired by a partnership between De Beers Group and master diamond manufacturer Diacore for an undisclosed sum (reported in some sources as around $40 million). Diacore, known for handling exceptional stones, spent nearly a year meticulously studying, cutting, and polishing the rough into a 15.10-carat step-cut rectangular diamond. This process involved significant risk due to the stone's rarity and value, with the final polish emphasizing its intense color and clarity. The Gemological Institute of America (GIA) graded it as Fancy Vivid Blue (the highest color grade for blues, given to less than 1% of submissions), Internally Flawless, and Type IIb—making it the largest such step-cut vivid blue ever graded by the GIA and the largest vivid blue to appear at auction.
Auction and Sale
Named the De Beers Cullinan Blue in honor of its mine and the De Beers collaboration, the diamond was unveiled in February 2022 and toured globally (including stops in New York, London, Dubai, and Asia) before its standalone auction at Sotheby's Magnificent Jewels sale in Hong Kong on April 27, 2022. Estimated at over $48 million, it sold after intense bidding for HK$450,925,000 (approximately US$57.47 million) to an anonymous private collector via telephone. This set a new record for the highest price per carat for a blue diamond at about $3.8 million, surpassing the previous benchmark held by the 12.03-carat Blue Moon of Josephine (sold for $48.5 million in 2015). It fell just short of the overall record for a vivid blue diamond, held by the 14.62-carat Oppenheimer Blue ($57.54 million in 2016).
Post-Sale History and Controversies
Since the 2022 sale, there have been no public updates on the diamond's ownership, resale, or current location as of January 2026—it remains in private hands with no reported exhibitions or further auctions. The diamond's history is not without ethical scrutiny: While certified conflict-free, its association with De Beers has drawn criticism due to the company's historical role in South Africa's diamond industry during apartheid, including labor exploitation and market monopolization. However, the Cullinan Mine's modern operations under Petra emphasize sustainable practices, and blue diamonds like this one represent less than 0.01% of global production, underscoring their geological rarity.
This diamond exemplifies the enduring allure of blue gems, with historical parallels to famous blues like the Hope Diamond (cut from the 17th-century Tavernier Blue).
At 15.10 carats, the rare @debeersgroup Cullinan Blue Diamond is the largest vivid blue diamond ever to appear at auction and the largest internally flawless step cut vivid blue diamond that the Gemological Institute of America (GIA) has ever graded. https://t.co/7Ch6cfAN8r pic.twitter.com/yscMNqGC1l
— Sotheby's (@Sothebys) February 16, 2022
