The Mediterranean Blue Diamond: A $21.5M Masterpiece That Stunned the World at Sotheby’s Geneva

In the elite realm of high jewelry, few events stir excitement like the unveiling of a once-in-a-generation gemstone. At Sotheby’s recent High Jewelry Auction, The Mediterranean Blue, a 10.03-carat, cushion-cut fancy vivid blue diamond, captivated global attention as it sold for an impressive $21.5 million. Acquired by a private American collector, with Sotheby’s Vice Chairman Frank Everett facilitating the purchase, this exceptional diamond now holds the distinction of being the most valuable jewel auctioned in 2025, an honor as striking as the gem’s deep, oceanic brilliance.

A Rarity Beyond Measure:

Discovered in 2023 at South Africa’s renowned Cullinan mine, The Mediterranean Blue stands out not just for its origin, but for its extraordinary classification. This rare gem holds the “Fancy Vivid Blue” grade, the highest color intensity standard recognized by the Gemological Institute of America (GIA). Its Type IIb diamond classification places it in an elite group comprising under 0.5% of all diamonds worldwide. Blue diamonds themselves are exceptionally rare, with fewer than 0.1% displaying any blue hue, and even fewer achieving the level of saturation seen here. The Cullinan mine, which has produced legends like the 530-carat Great Star of Africa and famous blues like the Blue Moon of Josephine and De Beers Blue, now adds another icon to its legacy.

Six Months of Artistry and Precision:

The original 31.94-carat rough diamond underwent more than a year of careful examination, followed by six months of precision cutting and polishing. The result is a cushion-modified brilliant cut designed to enhance the stone’s vivid blue hue while offering a soft, refined silhouette. With its balanced blend of heritage and modern craftsmanship, the diamond stands as both a tribute to history and a creation of contemporary elegance.

A Global Tour for a Global Icon:

Before its spotlight moment in Geneva, The Mediterranean Blue toured globally, enchanting audiences from Abu Dhabi, where it debuted at Sotheby’s inaugural exhibition in the UAE, to key cities across the Middle East, Asia, and the United States. In a creative fusion of fashion and fine jewelry, designer Lauren Harwell Godfrey was commissioned to conceptualize a brooch around the gem, inspired by the 2025 Met Gala theme, “Superfine: Tailoring Black Style.” In the end, however, the diamond was unveiled in a refined, minimalistic ring setting, allowing its natural radiance to take center stage.

A Defining Moment in Jewelry History:

With bidding that opened at CHF 9 million (around $10.7 million) and extended over a suspenseful three minutes, the sale of The Mediterranean Blue demonstrated once again the strong international demand for extraordinary gemstones. “It is undoubtedly the defining stone of the season and ranks among the top blue diamonds we have sold," Quig Bruning, Sotheby’s head of jewelry, Americas & EMEA, said in a statement. “To witness the excitement it has generated throughout its global exhibition tour, culminating in today’s result, clearly reflects the growing global appetite for rare and impeccable diamonds, and a marked flight to quality among collectors who continue to seek the very best in the world.” [DeMarco, A. (2025, May 13). The 10.3-carat 'Mediterranean Blue' diamond fetches $21.5 million. Forbes. https://www.forbes.com/sites/anthonydemarco/2025/05/13/the-103-carat-mediterranean-blue-diamond-fetches-215-million/]

Now part of the elite circle of legendary blue diamonds, The Mediterranean Blue has carved its place in auction history—and its story is far from over.

A Diamond That Redefines Elegance and Value:

Where hue meets heritage, The Mediterranean Blue emerges not just as a diamond, but as a beacon of timeless elegance and financial legacy.