10ct. Mediterranean Blue Nabs over $21M at Sotheby’s

Sotheby’s realized CHF 17.9 million ($21.5 million) for the Mediterranean Blue diamond Tuesday night at its Geneva auction, making it the most valuable jewel sold this year. 

Garnering $2.1 million per carat, the cushion modified brilliant-cut, 10.03-carat, fancy-vivid-blue, VS2-clarity diamond was the highlight of the auction house’s May 13 Geneva High Jewelry sale. It sold to an American private collector, Sotheby’s said Tuesday. While the stone attracted “enormous interest” overall, it was the target of a three-minute bidding war between two “determined” buyers, Sotheby’s explained. 

Petra recovered the 31.94-carat rough that was manufactured to create the Mediterranean Blue in 2023 from its Cullinan mine in South Africa. The final price fell within expectations, as Sotheby’s had priced it “in the region” of $20 million, but dealers believed it could have fetched up to $30 million. Anticipation was even higher once a consignor at Christie’s pulled the Golconda Blue, a pear-shaped, 23.24-carat, fancy-vivid-blue diamond estimated at up to $50 million, from the May 14 Geneva Magnificent Jewels sale at Christie’s.  

“The diamond did exceed its $20 million estimate, suggesting there was meaningful interest,” said Tobias Kormind, managing director of online diamond jeweler 77 Diamonds. “But broader uncertainty, including the ongoing US-China trade tensions, may have dampened bidder confidence and muted what could have been a more frenzied atmosphere.”