On Nov. 11 in Geneva, Sotheby’s will auction the Blue Moon, a 12.03 ct. internally flawless vivid blue estimated to sell for between $35 million and $55 million.
If it achieves the top price in that range, it will set a record for the most valuable diamond ever sold at auction. The current title is held by the Graff Pink, a 24.78 ct. fancy intense pink that sold for $46.1 million in November 2010.
The cushion brilliant-cut Blue Moon is among the few blues with a fancy vivid grade—the highest rating for a colored diamond—ever to go under the hammer.
The stone comes from a 29.62 ct. piece of rough discovered by Petra Diamonds at the Cullinan mine in South Africa in January 2014. It sold for $25.6 million a month later to New York City–based Cora International, which then spent six months cutting and polishing it.
A GIA monograph raved that the diamond’s color is “likely to have never before been seen within such a large diamond, or any gemstone… It could be indescribable to even the most experienced diamantaire or color theorist; some, however, liken it to the ocean.”
A video about the diamond can be seen here.
“Weighing in at 12.03 carats, the Blue Moon diamond is a simply sensational stone of perfect color and purity,” said David Bennett, worldwide chairman of Sotheby’s international jewelry division, in a statement. “Blue, for me, is the most mysterious and magical of all the colors of diamond, and the Blue Moon will now take its place among the most famous gems in the world.”