A celestial blue flame has been captured. At Sotheby’s Geneva on May 13, the world watched as the 10.03-carat Mediterranean Blue diamond — a Fancy Vivid Blue of arresting clarity and depth — crossed the auction block at an astonishing $21.5 million sale. Its name evokes the calm of ancient seas, but the sale was anything but tranquil. A fierce bidding war erupted, with the opening offer of 9 million Swiss francs rocketing upward in minutes — a dazzling reminder of the unrelenting global appetite for rare coloured diamonds.

Before it ignited the bidding room, this elusive gem had already caught the eye of the fashion elite. Just weeks earlier, it shimmered on the Met Gala red carpet, set as the centerpiece of a custom brooch by designer Lauren Harwell Godfrey in collaboration with Sotheby’s. Draped in myth and modernity, the Mediterranean Blue made its debut not in a vault, but in the cultural moment of the year.
Discovered in 2023 at the legendary Cullinan Mine in South Africa, the same origin as the famed Great Star of Africa, this ocean-hued diamond joins a pantheon of blues that have mesmerized collectors and gemologists alike. The Cullinan has long been the cradle of such marvels — from the Blue Moon of Josephine (sold for $48.5 million in 2015) to the De Beers Blue (which fetched $57.5 million in 2022). The Mediterranean Blue, though younger, has already earned its place among these storied names.
The Mediterranean Blue: A Global Journey Before The Sale
Its journey was global — unveiled first in Abu Dhabi, it then toured through Asia and the United States before arriving in Geneva for the moment of reckoning. A phone bidder, represented by Frank Everett, vice chairman of jewelry at Sotheby’s Americas, ultimately won the prize, securing a stone that had already become one of the most buzzed-about jewels of the season.
“It is undoubtedly the defining stone of the season,” said Quig Bruning, head of jewelry for Sotheby’s Americas & EMEA. “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.”
An Enchanting Story of Rarity

Indeed, the sale underscores a trend that continues to shape the ultra-high-end jewelry market: a passionate pursuit of rarity, color, and geological poetry. According to the International Gemological Institute (IGI), only one in 10,000 gem-quality diamonds is naturally colored — and among those, blues are among the most exceptional. A mere 0.3% of diamonds exhibit a predominantly blue hue, and stones over 10 carats are as rare as eclipses.
What gives these diamonds their celestial tone? The secret lies in the presence of boron within the diamond’s crystal lattice — an element so elusive, it turns light into magic. Boron absorbs yellow wavelengths, leaving only the oceanic glow that blue diamonds are prized for. It’s chemistry masquerading as myth.
The Mediterranean Blue arrives on the heels of other blockbuster blue diamond sales. In 2023, the Bulgari Laguna Blu, an 11.16-carat cushion-cut sapphire-toned diamond, sold for $25 million after dazzling on Priyanka Chopra at the Met Gala. Shortly after, Christie’s brought down the hammer on the Bleu Royal, a 17.61-carat masterpiece, for $44 million.
But even amid such sparkling competition, the Mediterranean Blue sale stands apart — a rare alchemy of provenance, color, and perfect timing. It’s not merely a diamond. It’s a story. A siren song in stone.
Featured image: Sotheby’s

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