Ocean Depths: Sotheby’s to Auction the Fancy Vivid Mediterranean Blue Diamond 

Some diamonds are built differently. They’re larger, rarer, more chemically unusual, and, let’s face it, more beautiful to look at. The Mediterranean Blue diamond is one such superstar of the carbon world, weighing in at more than 10 carats and boasting the most exceptional fancy vivid blue colouration. This sensational stone is due to be unveiled globally in Abu Dhabi on April 8 and will be auctioned by Sotheby’s Geneva on May 13. Before the bidding flurry commences, let’s take a closer look at this rare blue specimen that’s estimated to sell for in the region of US$20 million. 

Whenever we call something rare, it is important to put that rarity into context. The Mediterranean Blue diamond that will soon come up for auction has been categorised by the Gemological Institute of America (GIA) as Type IIb – a classification that represents less than 0.5% of all diamonds. Now, factor in its specifications: fancy vivid blue colour grade, a large weight of 10.03 carats, and fantastic clarity of VS2. Finally, let’s consider the fact that blue diamonds make up less than 0.02 per cent of all naturally mined diamonds. All these things combined make The Mediterranean Blue diamond a gem that’s genuinely worthy of the word ‘rare’. 

GIA describes The Mediterranean Blue diamond as a “symbol of nature’s eternal wonders” and adds that only 0.3% of diamonds display a colour that can be described as “predominantly blue”. The incredible saturation of this hue is further enhanced by the modified brilliant cushion cut, which adds softness to contrast the triangular and kite-shaped facet patterns. We’re told that the original rough, weighing 31.94 carats, was mined in South Africa in 2023 and required more than a year of careful analysis before cutting began. This process took a further six months, making The Mediterranean Blue a true labour of love. 

If a blue diamond is discovered, it is likely to be from (although not exclusively from) the Cullinan mine in South Africa. According to Sotheby’s, less than 0.1% of any diamonds sourced show any evidence of blue colour, which is caused by trace impurities of boron within the crystalline lattice structure. However, Cullinan has birthed some treasures, such as the Blue Moon of Josephine – a 12.03-carat cushion-shaped internally flawless vivid blue diamond that sold for US$48.5 million (US$4,028,941 per carat) at Sotheby’s Geneva in 2015 - and more recently The De Beers Blue, a 15.10 step-cut fancy vivid blue diamond, which sold for US$57.5 million in 2022 at Sotheby’s Hong Kong.

If you’d like to cast your eyes on this gem before it enters a private collection, now’s your chance! The Mediterranean Blue diamond will be unveiled in a special exhibition hosted at the Bassam Freiha Art Foundation, a non-profit institution on Abu Dhabi’s landmark Saadiyat Island Cultural District. After that introduction, it will be showcased in Taipei, Hong Kong and New York before its exhibition and sale in Geneva. Will the sale smash the US$20 million estimate? We can’t wait to find out.