8.01-Carat 'Sky Blue Diamond' Could Fetch $25M at Sotheby's Geneva

"The Sky Blue Diamond" is the latest in a procession of majestic fancy vivid blue diamonds that have captivated the auction world over the past 12 months.

Weighing 8.01 carats, "The Sky Blue Diamond" is the headliner of Sotheby’s Magnificent Jewels and Noble Jewels sale, which is set to take place in Geneva on November 16. The square-cut gem, which is set in a ring by Cartier, boasts the highest possible color grading, an excellent polish and a purity rating of Type IIb, a rare category representing less than 0.5% of all diamonds. Sotheby's set the pre-sale estimate at $15 million to $25 million.

If the ring sells at the top of the estimated range, it would yield $3.12 million per carat and rank among the finest fancy vivid blue diamonds of all time.

Blue diamond lovers may remember that "The Blue Moon of Josephine" established a new record for the highest price paid per carat for any gemstone when the hammer went down at Sotheby's Geneva in November 2015. The internally flawless 12.03-carat cushion-shaped fancy vivid blue diamond sold for $48.5 million, or $4.03 million per carat.

In May 2016, "The Oppenheimer Blue" became the priciest gem ever auctioned when it sold for $57.5 million at Christie's Geneva. The fancy vivid blue step-cut, rectangular-shaped diamond weighed 14.62 carats and earned a clarity rating of VVS1. Its price per carat was $3.96 million.

“The Sky Blue Diamond is of a wonderfully clear celestial blue, presented in an extremely elegant square emerald cut – in my view, the most flattering of all the cuts for a colored diamond," commented David Bennett, Worldwide Chairman of Sotheby’s International Jewelry Division. "This important gem will, I am sure, captivate all collectors of exceptional gemstones.”

The Sky Blue Diamond and other top lots from the Magnificent Jewels and Noble Jewels sale will tour London (October 13-17) and New York (November 4-6) before returning to Geneva for the auction.

Credits: The Sky Blue Diamond and The Blue Moon of Josephine images courtesy of Sotheby's. The Oppenheimer Blue image courtesy of Christie’s.