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If diamonds are a girl’s best friend, then the De Beers Cullinan Blue is surely the ultimate confidante. The largest vivid blue diamond ever to appear at auction, the stunning stone will go under the hammer at Sotheby’s Hong Kong this April.
Last worn by the Queen Mother for the Coronation of her husband King George VI, this storied crown has been worn by just three royal consorts, with the central diamond originally acquired by Queen Victoria
A 15.10 carat step-cut blue diamond, the rough stone was discovered in April last year. In its new form as the De Beers Cullinan Blue, the stone is one of the most valuable blue diamonds ever offered at auction and the largest vivid blue to go under the hammer in history. It is also the biggest internally flawless step cut vivid blue diamond ever graded by the Gemological Institute of America (GIA).
Blue diamonds are exceptionally rare, occurring when trace amounts of the element boron are found within the diamond crystal lattice. There are only a handful of mines where they can be sourced, and most discovered to date have been recovered from the Cullinan mine in South Africa (Cullinan has been the source of many famous diamonds, including the 530-carat Great Star of Africa, the biggest faceted colourless diamond in the world; and the central stone in the Queen’s Cullinan V diamond brooch).
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Sotheby’s explains the even greater rarity of blue diamonds of this importance, with only five predecessors over 10 carats having come to auction before – and none over 15 carats. One notable forebear was the De Beers Millennium Jewel 4, a 10.10 carat oval-shaped Fancy Vivid blue that sold for $31.8 million at Sotheby’s Hong Kong in April 2016, which was also a Cullinan diamond. The estimated value of the De Beers Cullinan Blue, however, is even greater, at more than $48 million (over £35 million).
The De Beers Cullinan Blue has achieved the highest rankings ever in judgements on its quality, graded Fancy Vivid Blue by the GIA (the highest possible colour grading); as well as being deemed Internally Flawless in clarity; with excellent polish; and to be of Type IIb – a rare category which makes up only 0.5 per cent of all diamonds. As for its cut, it’s step-cut style, most commonly most associated with white diamonds, is particularly rare in their coloured siblings, with blue diamonds in particular being notoriously difficult to cut.
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Blue diamonds have long been regarded as special treasures, with records indicating that Jean Baptiste Tavernier once sold a dark blue diamond to King Louis XIV of France in the 17th century. Originally called the Tavernier Blue, it then became known as the French Blue and became part of the French Crown Jewels.
Bruce Cleaver, CEO of De Beers Group, said of the sale: ‘This diamond ranks as one of the best De Beers has ever seen. It is extremely rare and unique, and as the Home of Diamonds, De Beers is pleased to join together with Sotheby’s to bring this diamond to the world.’
The De Beers Cullinan Blue will be sold at live auction in Hong Kong on 27 April. For more information, visit sothebys.com.
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