A rare Fancy Vivid Blue diamond known as The Mediterranean Blue has sold for CHF 17.9 million (approximately €19.9 million) during Sotheby’s High Jewelry auction in Geneva, drawing global attention and igniting a tense three-minute bidding battle.
The 10.03-carat cushion modified brilliant-cut stone, unearthed last year from South Africa’s historic Cullinan mine, was the undisputed highlight of Tuesday night’s sale. It ultimately went to an American private collector bidding via phone, represented by Frank Everett, Vice Chairman of Jewelry for the Americas. The final price nearly doubled its opening bid of CHF 9 million.
Its appearance on the market had been anticipated for months following a high-profile global tour that included stops in Abu Dhabi, Hong Kong, and New York. First unveiled during Sotheby’s inaugural exhibition in the UAE capital, The Mediterranean Blue was showcased alongside over $100 million worth of gems, helping generate immense interest ahead of its Geneva debut.
Quig Bruning, Sotheby’s Head of Jewelry for the Americas and EMEA, described the stone as “undoubtedly the defining diamond of the season,” noting the excitement it sparked among collectors worldwide. “It is a powerful reflection of the current flight to quality in the market,” he said.
The sale capped off a strong night for Sotheby’s, which recorded CHF 42 million in total auction results, with an impressive 99% of lots sold by value. The event was marked by particular interest from U.S. buyers, who were the leading group of bidders and buyers.
Blue diamonds dominated the session, with two other notable examples also exceeding expectations. A 5.83-carat Fancy Light Blue diamond ring fetched CHF 1.2 million, while a 4.05-carat Fancy Blue diamond pendant achieved CHF 952,500. The second most valuable lot of the evening was a pair of cushion-cut colorless diamonds weighing 23.88 and 23.76 carats, sold together for CHF 3.2 million.
The Mediterranean Blue belongs to the Type IIb category, a rare classification that includes less than 0.5% of all diamonds. Its intense saturation and soft cushion shape reflect over a year of study and six months of cutting and polishing following its discovery in a 31.94-carat rough stone. Experts describe it as a once-in-a-generation gem that now joins the ranks of other iconic Cullinan diamonds, including The Blue Moon of Josephine and The De Beers Blue.
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