‘Rarest of the Rare’ Blue Diamond Expected to Top $48M at Auction
The 15.10-carat fancy vivid blue, mined by Petra last spring and purchased by De Beers and Diacore, heads to Sotheby’s in April.

Sotheby’s announced Wednesday it will offer the 15-carat fancy vivid “De Beers Cullinan Blue Diamond” in a single-lot sale this spring.
The diamond is estimated to sell for more than $48 million, or $3.2 million per carat.
Mining company Petra Diamonds uncovered the original rough, weighing 39.34 carats, at the Cullinan mine in April 2021.
De Beers Group and manufacturer Diacore International, a De Beers sightholder and master diamond cutter, purchased the stone for $40.2 million last July.
Since then, the companies have been analyzing, cutting and polishing the stone to bring the diamond that’s been dubbed the De Beers Cullinan Blue to life.

What emerged is an internally flawless 15.10-carat step-cut fancy vivid blue diamond Sotheby’s is calling the largest vivid blue diamond ever to appear at auction.
The GIA Monograph Report on the stone states: “Achieving a fancy vivid color grade in a step cut or emerald cut adds to the rarity, since most other fancy shapes intensify the body color more efficiently in the face-up position than step cuts. To achieve a fancy vivid grade with a step cut or emerald cut, the inherent bodycolor has to be stronger than virtually every other fancy shape.”
Sotheby’s will offer the diamond in a live single-lot auction in late April—tentatively April 27—anchoring Sotheby’s Hong Kong Luxury Week.
Prior to that, it will be showcased in a worldwide tour, starting in New York before traveling to London, Dubai, Shanghai, Beijing, Shenzhen, and Taipei.

“Blue diamonds of any kind are rare on the market, but this is the rarest of the rare; nothing of remotely similar caliber has appeared at auction in recent years. Hundreds of millions of years in the making, this extraordinary blue diamond is surely one of nature’s finest creations,” said Patti Wong, chairman of Sotheby’s Asia.
“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, colored diamonds, we are incredibly excited to bring to the market what is sure to become one of the most celebrated gems in the world.”
According to Sotheby’s, only five blue diamonds weighing more than 10 carats have gone to auction before, with none exceeding 15 carats.
The world auction record for highest price per carat belongs to “The Blue Moon of Josephine,” a 12.03-carat internally flawless cushion-shaped fancy vivid blue diamond, which sold for $48.5 million, or about $4 million per carat, in November 2015.
The “Oppenheimer Blue,” a 14.62-carat fancy vivid blue step-cut diamond, sold for $57.5 million in May 2016, setting the record for the most expensive jewel sold at auction.
The 59.60-carat “Pink Star” diamond later eclipsed the Oppenheimer Blue, selling for $71.2 million in April 2017. It remains the most expensive jewel ever sold at auction.
The Latest

Located on Rodeo Drive, the store’s design was inspired by Hollywood and Los Angeles culture.

The new location continues the brand’s celebration of its 25th anniversary.

The online watch marketplace’s “Time Is Our Thing” campaign highlights the importance of time.

The Seymour & Evelyn Holtzman Bench Scholarship from Jewelers of America returns for a second year.

She will oversee strategic planning, fundraising, industry partnerships, and the launch of the Gem Legacy Campus in Tanzania.


Working with Amazon’s Counterfeit Crimes Unit and law enforcement, Pandora helped to shut down a large-scale counterfeit network in China.

The jewelry company has closed its three California brick-and-mortar stores, as well as its online shop, for now.

The countdown is on for the JCK Las Vegas Show and JA is pulling out all the stops.

The company is providing the opportunity for an FIT student to work alongside master diamond cutter Willie Lopez in its workshop.

He is remembered for his successful entrepreneurship, generosity, and dedication to his family.

The jewelry store chain has reportedly been struggling with costs related to tariffs as well as tough retail competition.

Welcome warm summer days with red hot rubies perfectly chosen as July’s birthstone.

Co-founders Afzal Imram and Lin Ruiyin brought their son’s story of a cosmic egg, toadstool, and railroad to life in their new collection.

The best time to prepare for the holiday season is right now, according to columnist Emmanuel Raheb.

This year’s winner is Morgan Keefe, who is currently studying at GIA to be a gemologist.

“The Jewelry Book” comes out this September.

The company is focused on modernizing the custom jewelry buying experience with e-commerce tools like product visualization and 3D styling.

Following its recent acquisition, the storied brand has updated its leadership team and regional managers.

AGS also named the recipient of its “Women in Leadership” scholarship.

The 20-karat yellow gold and diamond wrap ring is modeled after the Monstera plants in the garden of the brand’s Miami villa.

Rocksbox President Allison Vigil shared the retailer’s expansion plans, and her thoughts on opening stores in malls.

The creator of the WJA Chicago chapter is remembered as a champion for women in the jewelry industry and a loving grandmother.

The decline was consistent across age groups and almost all income groups, with tariffs and inflation still top of mind.

The “Playlist: Electric Dreams” collection brings lyrics from the musician’s song, “Little Wing,” to life through fine jewelry.

The event is set for May 16-19 in Detroit, Michigan.

The Vault’s Katherine Jetter is accusing the retailer of using info she shared for a potential partnership to move into Nantucket.

Agents seized 2,193 pieces, a mix of counterfeit Cartier “Love” and “Juste Un Clou” bracelets, and Van Cleef & Arpels’ “Alhambra” design.