10 Ct. Fancy Vivid Blue Diamond Could Achieve $20 Million At Sotheby‘s Auction

By Annie Davidson Watson | March 24, 2025

A once-in-a-lifetime gem is about to make its auction debut: The Mediterranean Blue, an extraordinary 10.03 ct. fancy vivid blue diamond, is heading to Sotheby’s High Jewelry Sale in Geneva on May 13. Estimated to fetch around $20 million (CHF 18 million), this rare piece will be showcased on a global tour, starting with an exclusive unveiling in Abu Dhabi on April 8 before traveling to Taipei, Hong Kong, and New York.

Graded by the Gemological Institute of America (GIA) as Fancy Vivid Blue, the Mediterranean Blue boasts an ocean-blue hue so rare that only a tiny fraction of diamonds exhibit such a striking color. “Like its namesake, the Mediterranean Blue is a symbol of nature’s eternal wonders,” said the GIA in a statement. “Its physical beauty, enhanced by the skill of a master cutter, is mesmerizing as is its blue color, so rarely seen; only 0.3% of diamonds display a color that would be described as predominately blue among all diamonds submitted to GIA annually and of those, only a small number are Fancy Vivid weighing 10 carats or more.” Even more exceptional, the diamond is classified as Type IIb, a designation reserved for less than 0.5% of all diamonds. Its cushion shape further highlights its saturation, making it one of the most sought-after stones in the world.

Quig Bruning, head of jewelry for Sotheby’s Americas and EMEA, added: “The Mediterranean Blue’s remarkable size, charming cushion-cut and ocean-blue color places it in the rarefied company of some of the most important blue diamonds to come to market in recent years.”

The Mediterranean Blue’s journey began in South Africa, where it was uncovered in 2023 as a 31.94 ct. rough diamond. After more than a year of planning and six months of meticulous cutting, the diamond was shaped into its current cushion-modified brilliant form. The careful faceting, including triangular and kite-shape cuts, maximizes its brilliance, ensuring it will shine in every light.

The jewel will be introduced to the public at the Bassam Freiha Art Foundation in Abu Dhabi, a space with exceptional architecture providing the perfect backdrop for such a wonder of a stone.

Sotheby’s is no stranger to record-breaking blue diamonds, with past auctions featuring iconic gems including the Blue Moon of Josephine and the De Beers Blue. With the Mediterranean Blue, collectors and connoisseurs alike can expect another history-making sale when this stone takes center stage this spring.

(Photo courtesy of Sotheby’s)

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