The Mediterranean Blue Diamond: A Rare Natural Wonder Is Set to Stun the World

In the world of auctions, few treasures rival the excitement, rarity, and enduring value of natural blue diamonds and Sotheby’s new Mediterranean Blue Diamond certainly fits that bill. Formed deeper within the Earth’s crust than any other diamonds, these mesmerizing gems are among the rarest natural phenomena in existence.

With less than one blue diamond coming to market for every 100 Picasso paintings, their scarcity alone makes them objects of immense desire. And now, an extraordinary new specimen is set to make waves in the auction world. The Mediterranean Blue diamond, a 10.03-carat Fancy Vivid Blue diamond, will take center stage at Sotheby’s High Jewelry Sale in Geneva on May 13, 2025, with an estimated value in the region of $20 million.

Unlike colorless diamonds, which are formed from primarily pure carbon, blue diamonds owe their mesmerizing hue to traces of boron, an element that becomes trapped in their crystal structure during formation. This presence of boron allows them to conduct electricity, which is a feature shared by only 0.5% of all diamonds classified as Type IIb. But what makes blue diamonds even more exceptional is where they come from. These rare gems are formed at extreme depths nearly four times deeper than most other diamonds and under conditions so unique that their creation is nearly impossible to replicate.

Discovery of the Mediterranean Blue Diamond

The Mediterranean Blue, discovered in 2023 at the Cullinan Mine in South Africa, is a fabulous example of this natural wonder. The mine, famous for producing some of the world’s most extraordinary diamonds, has been the source of many legendary blues, including The Blue Moon of Josephine, a 12.03-carat Fancy Vivid Blue diamond that sold for $48.5 million in 2015, and The De Beers Blue, a 15.10-carat step-cut Fancy Vivid Blue diamond that fetched $57.5 million in 2022 at Sotheby’s Hong Kong.

Less than one blue diamond comes to market for every 100 Picasso paintings. Their scarcity makes them objects of immense desire.

Announcing the sale of the Mediterranean Blue diamond, Quig Bruning, Sotheby’s Head of Jewelry, Americas & EMEA, commented, “The Mediterranean Blue represents one of nature’s rarest gems. Any vivid blue diamond is a discovery worth celebrating, but one as entrancing as this, particularly being over 10 carats, is a newsworthy event. 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.

Creating the Mediterranean Blue Diamond

Transforming a 31.94-carat rough diamond into a perfectly balanced 10.03-carat cushion-modified brilliant cut is no small feat. The process took over a year of meticulous study and six months of expert craftsmanship to maximize its clarity, brilliance, and saturation. The result? A masterpiece of nature and artistry, a diamond with an exceptional depth of color that places it among the most coveted Fancy Vivid Blue diamonds ever to appear at auction.

To celebrate its significance, Sotheby’s will unveil The Mediterranean Blue diamond with a global exhibition tour before its sale in Geneva. The journey begins in Abu Dhabi on April 8, 2025, before stopping in Taipei, Hong Kong, and New York, allowing collectors and connoisseurs to witness this rare gem firsthand.

A History-Making Diamond

History has shown that blue diamonds not only hold their value but appreciate over time, reinforcing the enduring worth of natural diamonds in the luxury market. Their scarcity, coupled with their timeless appeal, has driven record-breaking prices over the years. 

As The Mediterranean Blue prepares to make its grand debut on the auction stage, its rarity and significance cannot be overstated. Blue diamonds of this caliber appear at auction so infrequently that their sales become historic moments in the jewelry world. Whether this diamond sets a new benchmark remains to be seen. Still, one thing is sure: the Mediterranean Blue is not just a jewel but a once-in-a-lifetime discovery destined to captivate collectors and investors alike.