Rare blue diamond valued at more than $48 million goes on display at Sotheby's Dubai

The Cullinan Blue is the largest fancy vivid blue stone to go to auction in April

Sotheby's Dubai unveiled a rare blue diamond weighing 15.10 carats and estimated more than $48 million on display at the Dubai Diamond Exchange in Dubai on February 23. All photos: Pawan Singh / The National

Sophie Stevens, jewellery specialist at Sotheby's Dubai, holds the De Beers Cullinan fancy vivid blue diamond, the largest of its type to ever come to auction.

Expected to sell for more than $48m, only five other vivid blue diamonds above 10 carats have ever come to auction, making it the first 15-carat stone to be offered at auction.

The unique internal colour is enhanced by its step cut, the most technically demanding cut to work with. Master cutters at Diacore spent a year cutting and polishing the diamond to achieve the final result.

The exceptionally rare fancy vivid blue diamond will be on display in Dubai until February 26.

The rough stone, weighing almost 40 carats, was unearthed in April 2021 at the Cullinan mine in South Africa.

Certified by the GIA as internally flawless, the blue diamond was formed over millions of years.

One of the rarest diamonds in the world is going on display in Dubai on Wednesday until Saturday. Called the The De Beers Cullinan Blue, this 15.10-carat fancy vivid blue stone is not only rare, but it will also be the largest blue diamond to go to auction when it is sold at Sotheby’s Hong Kong in April.

Millions of years in the making, the rough stone, weighing almost 40 carats, was unearthed in April 2021 at the Cullinan mine in South Africa, famous for producing exceptional stones, including the 530-carat colourless Great Star of Africa that now sits in the Queen of England's sceptre.

Purchased by De Beers and Diacore for an estimated $40 million, the master cutters of Diacore spent almost a year cutting and polishing the stone to create an internally flawless diamond.

“Only five other vivid blue diamonds over 10 carats have ever come to auction, and none over 15 carats,” said Sophie Stevens, deputy director of Sotheby’s Dubai, at the grand unveiling on Wednesday.

“It is not only the size and colour that makes this stone so unique, it is the step cut, an extraordinarily difficult cut to master. It is the most complicated, and only the best of the best can perfect it. The master cutter who has worked this stone has managed not only this very difficult cut, but has maintained the unique colour and clarity."

The designation of "fancy vivid" is the rarest in diamonds, so using the step cut, while the most technically demanding, has created a large flat surface, that with the stepped sides help increase the intensity of the unique internal colour.

Describing it as a once-in-a-lifetime opportunity, Stevens urges the public to go and see this remarkable stone while it is in Dubai.

“This has been certified by the Gemological Institute of America as internally flawless, which is remarkable given the heat and pressure required to form it. The GIA only award this to 1 percent of all diamonds. It is a Type IIb [2B] stone, making it incredibly rare, and a classification given to less than 0.5 percent of all stones. Nothing of this size, colour and clarity has come to auction in many years, so it really is very exciting.”

First unveiled in New York, the diamond then travelled to London, before coming to Dubai. After Saturday, it will continue its tour via Singapore, Taiwan and Shanghai before it arrives in Hong Kong for its sale, where it is expected to sell for in excess of $48m.

Scroll through the photo gallery to see the rare 555-carat black diamond recently unveiled in Dubai: