In early November, 2015, the diamond world was rocked by a new world record: Sotheby’s announced that it has sold the Blue Moon, a 12.03-carat internally flawless vivid blue cushion cut diamond, for $48.5 million – the most fetched for any gemstone in any auction.
The stone was first discovered at the Cullinan mine in South Africa, weighing 29.62-carat in its rough form. It was then purchased by Cora International for $25.6 million. In an exclusive interview for JCK Online, Cora chairman Ehud Laniado spoke about the cutting process of this rare and valuable stone.
In figuring out the stone, Laniado explains, there are three parameters at work: first, the color, and the reflection of the color back to the eye; second, the yield of the rough, which affects the company’s margin; and last, the purity of the stone.
After weighing all these parameters, the experts at Cora Int. decided to go for the cushion cut – “considered the nicest shape for a blue stone”, and to cut it to 12 carats – the perfect weight, in that stone, to reflect back light. This took approximately five months of debating and evaluating all the possibilities, including the building of 12 different computerized models of the end result. Finally, the company went ahead with a 12 carat cushion shape stone for the “optimal model, the optimal purity, [and] the ultimate color”.
The cutters then went to work, and it was accomplished with “no physical or technical hiccups”.
According to Laniado, he had estimated that the stone would fetch $40 million to $45 million, so he was naturally very happy with the auction’s result.