From the mineralogical point of view, it is perfect : Type IIa, D color and internally flawless despite its large size.
Compared to other diamonds of same quality and comparable weight, it has the unique feature of being emerald cut, offering one of the best possible shine. It is estimated $ 19M, lot 357, and was the subject of a detailed press release.
I remind for references two white diamonds also of recent African origin previously discussed in this column.
On May 15, 2013, Christie's sold for CHF 26M including premium a pear shaped diamond weighing 101.73 carats. On October 7, 2013, Sotheby's sold for HK $ 240M including premium an oval diamond weighing 118.28 carats.
I invite you to play the video shared by Sotheby's :