Record-breaking blue diamond could fetch $48 million at auction

One of the most valuable blue diamonds to ever feature at an auction could sell for more than $48 million, according to Sotheby’s.

Named “The De Beers Cullinan Blue,” it is the biggest vivid blue diamond to be put up for auction, according to a press release from Sotheby’s Wednesday.

The 15.10-carat gem is also “the largest internally flawless step cut vivid blue diamond” to be appraised by the Gemological Institute of America (GIA), the press statement said.

Describing the diamond as “exceptionally rare,” Sotheby’s added that only five gems over 10 carats have ever appeared at auction. None have ever been over 15 carats, “making the appearance of this flawless gem a landmark event in itself.”

The rare diamond was found in the Cullinan mine, South Africa, in 2021, and has attained the highest rankings, according to the standards that colored diamonds are judged by.

It was categorized as “fancy vivid blue” by the GIA — the highest possible color grading, which has been awarded to no more than 1% of blue diamonds submitted to the organization.

The jewel has outstanding polish, and is of Type IIb, which means it contains boron and therefore has a bluish gray shade, according to the GIA website. Less than 0.5% of diamonds are part of such a category, the press statement said.

“Blue diamonds of any kind are rare on the market, but this is the rarest of the rare; nothing of remotely similar calibre has appeared at auction in recent years,” Patti Wong, chairman of Sotheby’s Asia, said in the press statement.

“Hundreds of millions of years in the making, this extraordinary blue diamond is surely one of nature’s finest creations. Now brought to dazzling life by the hand of one of the world’s most skillful cutters, it is the ultimate masterpiece — as rare and desirable as the very greatest works of art.

“At a time of unprecedented demand for the finest, world-class, coloured diamonds, we are incredibly excited to bring to the market what is sure to become one of the most celebrated gems in the world.”

Blue diamonds are coveted due to their rarity and striking coloring, the press statement said.

The Cullinan mine has produced an array of valuable gems, including the 3,106-carat Cullinan Diamond discovered in 1905, which is the largest diamond ever recorded, according to the Cape Town Diamond Museum in South Africa.

The “Blue Moon of Josephine” is a 12.03 carat blue diamond that sold for $48.4 million in 2015. It still holds the auction record for the price-per-carat of any diamond or gemstone, the press statement said.

Other recent discoveries include “The Sakura,” a 15.81-carat purple-pink diamond that sold for $29.3 million at Christie’s in May last year.

“The De Beers Cullinan Blue” is scheduled to go up for auction in a standalone event at Sotheby’s Hong Kong Luxury Week in late April.