The Mediterranean Blue—A $21.5 Million Blue Diamond Breaks Records

In May 2025, Sotheby’s Geneva auction unveiled and sold a 10.03-carat Fancy Vivid Blue diamond dubbed The Mediterranean Blue for an astounding $21.5 million, surpassing its pre-sale estimate and making it the most valuable gem sold that year Only Natural Diamonds+13nationaljeweler.com+13UAE Times Now+13.

This cushion-modified brilliant-cut gem, graded by GIA as Fancy Vivid Blue, VS2 clarity, and Type IIb (a classification held by fewer than 0.5% of diamonds), sparked a fierce three-minute bidding war and remains a milestone in the colored diamond market Bretagne Sud Sotheby's Realty+7nationaljeweler.com+7Sothebys.com+7.

Cut from a 31.94-carat rough diamond discovered in 2023 at South Africa’s Cullinan mine, the gem underwent a year of analysis and six months of expert cutting to optimize its color, size, and brilliance Roskin Gem News Report+6nationaljeweler.com+6MINING.COM+6.

Sotheby’s showcased the diamond globally—beginning in Abu Dhabi before heading to Geneva—further enhancing its allure Instagram+13Sothebys.com+13Only Natural Diamonds+13.

This sale underscores the enduring prestige and financial gravitas that rare natural colored diamonds command among collectors and investors.