‘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

Collectibles platform Arena Club’s new Time Boxes could contain a Rolex or Patek Philippe watch.

The “Constellation Plié” collar, our Piece of the Week, features diamonds arranged in a constellation of shining stars.

Shaun Wills joined the company in 2024 and was chief financial officer of the De Beers Brands and Consumer Markets division.

Colored gemstones, artisan finishes, mixed metals, and meaningful details are shaping demand in bridal jewelry.

In honor of its 20th anniversary, the jewelry brand has released a limited-edition collection of Swiss-made timepieces.


“Human Being” highlights the similarities and differences between us through five sets of jewelry that celebrate fine craftsmanship.

Richemont will continue to provide operational services for the watch brand for a period while the group prepares to integrate it.

DCA is preparing the next generation of professionals by supporting workforce development, leadership growth, and career advancement.

Enoch Platero, founder and designer behind Enoch Michael, is the first Native American jeweler to win the award.

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

The founder of the billion-dollar jewelry and lifestyle brand will debut as a full-time “Shark” on the upcoming season of the show.

Plus, why retailers should be ready to adjust as the U.S. population may decline this year for the first time since the Great Depression.

René Lalique’s “Woman Dragonfly With Open Wings” pendant, the first piece the museum acquired, was one of the jewels taken.

Arien Gessner and Moss Makhoulian have been elevated into newly created roles.

A podcast prompted Smith to share his views on where origin fits into the natural diamond story and the viability of branded diamonds.

The association selected eight recipients for the funding program, which is in its second year.

Whether celebrating America’s 250th birthday or the USA’s World Cup run, July birthstone jewelry can double as a patriotic accessory.

Around 20 pieces of jewelry were stolen from the museum dedicated to French jeweler and glassmaker René Lalique.

The “Summer of ’96” campaign and collection celebrate the year the brand was founded for its 30th anniversary.

After eight years, Gilbertson is leaving his post at the mining company, which is currently facing a slew of operational challenges.

The new location is set to open this winter, featuring the retailer’s first rotating jewelry designer residency.

The pop artist appears in the latest campaign for the “Laurence Graff Signature” collection.

One-of-a-kind pearls take the shape of ice cream cones, frogs, submarines, and other imaginative charms.

Charlotte Rose said her election is “a sign that this is an industry capable of change.”

Sponsored by Rio Grande Jewelry Supply

The American jewelry house, founded by Latvian immigrants, has been creating American flag brooches since 1917.

The artwork celebrates the Atlanta jeweler’s legacy and symbolizes its commitment to supporting local artists and its community.

























