Blue diamond by sothebyBlue diamond by sotheby

The World’s Largest Fancy Vivid Blue Diamond Expected to Auction for $48 Million


3 Minute Read

HomeLearning CenterGemologyGem and Jewelry NewsThe World’s Largest Fancy Vivid Blue Diamond Expected to Auction for $48 Million

Blue diamond by sotheby
Photo by Sotheby's

A 15.1-carat fancy blue vivid diamond will hit Sotheby's Hong Kong auction block in April with a starting price of USD$48 million, the highest estimate ever for a blue diamond.

The 'De Beers Cullinan Blue Diamond' — named for the South African mine where it was discovered in April 2021 — is also the largest fancy vivid blue diamond ever to appear at auction.

"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," Sotheby's Asia chairwoman, Patti Wong, said in a press statement

In fact, Sotheby's says only five gems over 10 carats have ever appeared at auction, and none have been over 15 carats, "making the appearance of this flawless gem a landmark event in itself." 

Even the Gemological Institute of America (GIA) considers this diamond one of a kind, calling it "the largest internally flawless step-cut vivid blue diamond" it has ever graded, explaining that just 1% of blue diamonds submitted to the organization are ever even awarded this remarkable color grade of "fancy vivid blue."

Just like colorless diamonds, colored diamonds are formed naturally out of carbon deep below the surface of the Earth at temperatures greater than 1000 degrees Celsius over the course of millions of years. However, just 0.1% of all diamonds end up with a fluke, altered chemical structure, giving them stunningly rare color. In the case of blue diamonds, boron is trapped inside the rough diamond during formation, creating color that ranges from blue-green to blue-purple with different intensities. 

Most blue diamonds are grey with a tint of blue creating a 'steely' color, but as saturation increases, blue diamond ratings go from 'fancy' to 'fancy intense' and the ultra-rare 'fancy vivid' like the 'De Beers Cullinan Blue Diamond'.

"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," Wong went on to say.

While colored diamonds are found all over the world, the Cullinan mine in South Africa where it was found is one of the few known to boast blue diamonds. The mine has famously yielded some of the world's most precious diamonds, like the 3,106 carat 'Cullen Diamond' from 1905, and more recently, the De Beers Millennium Jewel 4, a 10.10 carat fancy vivid blue, oval-shaped diamond that sold at Sotheby's Hong Kong in April 2016 for $31.8 million. 

Today, the mine is owned by Petra Diamonds Ltd., which acquired it from De Beers in 2008.

But as Sotheby's notes, what also makes this blue diamond exceptional is the cut. Diacore, a leading diamond manufacturer and cutter, was trusted with the step-cut and polishing of the rough diamond over the last year — a style renowned for its use in white diamonds, but highly sought-after in rare colors. 

"…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," the GIA Monograph explained. 

But achieving the cut is easier said than done. As one of the hardest materials on earth, incredible skill and precision is needed to cut them. "With blue diamonds, the challenge is yet greater: because of their formation, every faceting process of a blue diamond demands extreme care and precision," Sotheby's explained in their press statement. "There is zero tolerance for miscalculation; any minute error would result in a loss of color and destruction of the beauty."

Now, with internally flawless clarity and excellent polish that results in sparkle and high light return, the 15.1-carat fancy blue vivid 'De Beers Cullinan Blue Diamond' will hit Sotheby's auction block at an undisclosed date in April. 

However, before that, the diamond will first travel to London, Dubai, Singapore, Shanghai, Beijing, Shenzhen, and Taipei where it will sit on exhibition before being sold in Hong Kong. 


Cate Misczuk

Cate Misczuk is a jewelry and watch writer who covers everything from the latest jewelry trends and the heritage of watchmaking to 24k gold, gems, sustainability, unisex timepieces and more. Get in touch at catemisczuk.com.

Related Articles

More Articles
More Couples Embracing Custom Engagement Ring TrendSarah Something Photography</a>." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

More Couples Embracing Custom Engagement Ring Trend

March 29, 2022 When Jessica Ames, 26, and Celia Hansen, 28, got engaged last year, both women ended up having...
Read More
De Beers Cullinan Blue Diamond Nearly Breaks World Record Auction Price

De Beers Cullinan Blue Diamond Nearly Breaks World Record Auction Price

May 6, 2022 The largest vivid blue diamond to ever appear on auction sold for a staggering sum at Sotheby's...
Read More
The Best Gilded Age Jewelry at the Met Gala 2022: Tiaras, Chokers, and Nail Guards Fit For A Chinese Empress

The Best Gilded Age Jewelry at the Met Gala 2022: Tiaras, Chokers, and Nail Guards Fit For A Chinese Empress

May 9, 2022 It’s been a week since the Met Gala red carpet, but people just can’t seem to stop...
Read More
EU and UK Sanctions on Russia Continue to Exclude Diamonds

EU and UK Sanctions on Russia Continue to Exclude Diamonds

March 25, 2022 This week members of the European Union (EU) discussed increasing sanctions against industries tied to Russia’s government....
Read More

Latest Articles

More Articles
Classic Engagement Ring StonesPastel purple sapphire</a>, 1.08 cts, 5.8 mm, round cut, Sri Lanka. © <a href=https://www.gemsociety.org/news/2022/03/08/worlds-largest-fancy-vivid-blue-diamond-expected-auction-48-million/"https://www.thegemtrader.com/">The Gem Trader</a>. Used with permission." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Classic Engagement Ring Stones

Emerald, ruby, sapphire, and diamond are the most popular choices for classic engagement ring stones. Learn more about these traditional...
Read More
Broken Bangle — The Blunder-Besmirched History of Jade Nomenclature: Book Review

Broken Bangle — The Blunder-Besmirched History of Jade Nomenclature: Book Review

Is fei cui a better term for "pyroxene jade" than jadeite? Jeffery Bergman reviews Broken Bangle, a new book on...
Read More
Cuprite Value, Price, and Jewelry InformationJoel E. Arem</a>, PhD, FGA. Used with permission." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Cuprite Value, Price, and Jewelry Information

One of the rarest of all facetable gems, cut cuprites can show magnificent deep red color. However, these beautiful stones...
Read More
Gemstone Radiation TreatmentPhoto courtesy of <a href=https://www.gemsociety.org/news/2022/03/08/worlds-largest-fancy-vivid-blue-diamond-expected-auction-48-million/"https://www.liveauctioneers.com/">liveauctioneers.com and <a href=https://www.gemsociety.org/news/2022/03/08/worlds-largest-fancy-vivid-blue-diamond-expected-auction-48-million/"https://www.liveauctioneers.com/auctioneer/1081/eros-auctions-inc/">Eros Auctions, Inc</a>." src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" decoding="async" data-nimg="responsive" style="position:absolute;top:0;left:0;bottom:0;right:0;box-sizing:border-box;padding:0;border:none;margin:auto;display:block;width:0;height:0;min-width:100%;max-width:100%;min-height:100%;max-height:100%;object-fit:cover;object-position:50% 50%"/>

Gemstone Radiation Treatment

Gemstone radiation is a common but little understood technique for altering colors. Learn how it works and what gems usually...
Read More

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!