A 15.10-carat Fancy Vivid blue diamond named “The De Beers Cullinan Blue” recently sold for HK$451 million / US$57.5 million at Sotheby’s in Hong Kong. This rare 15.10-carat baguette-cut fancy vivid blue internally flawless diamond is the largest fancy vivid blue diamond ever sold at auction.
rarer than rare
This 15.10-carat baguette-cut Step-Cut blue diamond, from a rough stone weighing more than 40 carats discovered in April 2021, has been cut and polished to become the largest Fancy Vivid blue diamond ever sold at auction , the largest internally flawless step-cut Fancy Vivid blue diamond identified by the Gemological Institute of America (GIA). It is reported that only five blue diamonds above 10 carats have been auctioned so far, but they have never exceeded 15 carats like the "De Beers Cullinan Haoyu Blue".

"De Beers Cullinan Haoyu Blue" 15.10 carats

A rough 40-carat blue diamond was discovered at the Cullinan Mine in South Africa in 2021.

"De Beers Cullinan Haoyu Blue" has obtained the highest vivid color grade in the color evaluation of colored diamonds, which is commendable. Less than 1% of blue diamonds graded by the Gemological Institute of America (GIA) are of this grade. In addition, this diamond has an “Internally Flawless” clarity, has excellent polish, and is a Type IIb diamond of less than 0.5%.
This blue diamond also features a classic baguette step cut for added glamour. According to experts at the Gemological Institute of America (GIA), “Diamonds capable of Fancy Vivid in a square cut are extremely rare, as most other fancy cuts tend to intensify the color saturation of the diamond at a face-up angle compared to the baguette step cut. For a diamond cut to be Fancy Vivid, there are very high requirements for the color of the diamond itself, which must be more intense than other cut shapes.”
A gem of a legend
The unique color of blue diamonds is derived from trace amounts of boron in the crystal structure, which is extremely rare even in already very rare colored diamonds. Many diamond mines in the world can mine other colored diamonds, but there are only a few sources of blue diamonds, and most of the blue diamonds are produced in the Cullinan mine in South Africa. This legendary mine has produced some of the most prestigious diamonds in the world today, such as the Great Star of Africa, the largest faceted diamond weighing up to 530 carats. The Cullinan mine continues to produce many famous diamonds, including all DE BEERS blue diamonds, especially the 10.10-carat oval Fancy Vivid blue diamond "De Beers Millennium Jewel 4", The diamond sold for US$31.8 million / HK$248.28 million at Sotheby’s Hong Kong in April 2016.

The De Beers Millennium Jewel 4, a 10.10-carat oval-shaped Fancy Vivid blue diamond, sold for US$31.8 million / HK$248.28 million at Sotheby’s Hong Kong in April 2016 .

The rarity of blue diamonds in nature has attracted collectors from ancient and modern China and abroad. As early as the 17th century, it is recorded that Jean Baptiste Tavernier sold the blue diamond formerly known as the "Tavernier Blue" to King Louis XIV of France, and the diamond was subsequently renamed the "Tavernier Blue". Blue" (French Blue), belonging to the French Royal Jewelry Collection.
The largest blue diamond in existence is the legendary "Diamond of Hope". This 45.52-carat blue diamond has an extremely complicated story. Since the discovery of this diamond in 1666, it has experienced Louis XIV, Louis XV, Louis XVI, Rambona Princess, Banker Hope, McClain A series of masters such as Mrs. also created a series of tragic legends.

Hope Diamond

Jeweler Harry Winston bought the diamond in 1947 for $1.1 million. In the following 10 years, Winston traveled 640,000 kilometers with this diamond and other precious gems, and toured around the world to raise funds for charities. A total of 500 people visited the diamond, and a total of more than 100 donations were raised Ten thousand U.S. dollars. The diamond was eventually sent to the collection of the Smithsonian Institution in Washington. Because it is too legendary, this diamond has also become the inspiration for the creation of the "Ocean Star" necklace in "Titanic".
Brilliant milestones at auction
Only a handful of significant blue diamonds have made it to auction in the past 20 years. Until 2007, the 6.04-carat Fancy Vivid Internally Flawless Blue Diamond presented by Sotheby's was sold for a record-breaking $1,321,495 per carat, not only breaking the record held by the famous "Hancock Red Diamond" for 20 years, but also making the heavyweight blue diamond more expensive. Diamond price per carat hit another peak, jumping to over $1,000,000.
Since then, blue diamonds have been invincible at auction. In 2014, Mrs. Mellon's Fancy Vivid blue diamond (later named "Zoe Diamond") sold for $32,600,000 ($3,348,205 per carat) at Sotheby's in New York. This auction record was broken again in 2015 when Sotheby's Geneva sold the 12.03-carat antique cushion-shaped Fancy Vivid internally flawless blue diamond "The Blue Moon of Josephine" for $48,500,000 ($4,028,941 per carat), which still remains today Holds the auction record for the highest price per carat of any diamond or gemstone. The most expensive moment blue diamond currently sold at auction is a 14.62-carat Fancy Vivid blue diamond called “The Oppenheimer Blue,” which sold at Christie’s Geneva in 2016 for $57,541,779 ($3,935,826 per carat).
Here are 5 blue diamonds that have performed exceptionally well in auction history:

“The Blue Moon of Josephine,” a 12.03-carat Fancy Vivid blue diamond, cushion-cut, internally flawless, Sotheby’s Geneva, November 2015, sold for $48,468,158 ($4,028,941 per carat) ).

“The Oppenheimer Blue,” a 14.62-carat Fancy Vivid blue diamond, baguette-cut, VVS1 clarity, Christie’s Geneva, May 2016, sold for $57,541,779 ($3,935,826 per carat).

“The Zoe Diamond,” a 9.75-carat Fancy Vivid blue diamond from the Mrs. Mellon Collection, pear-shaped, VVS2 clarity, Sotheby’s New York, November 2014, sold for $32,645,000 ($3,348,205 per carat).

“The Memory of Autumn Leaves,” a 14.54-carat Fancy Vivid blue diamond, pear-shaped, internally flawless, Sotheby’s Geneva, May 2017, sold for $42,087,302 ($2,894,587 per carat).

The Sky Blue Diamond, an 8.01 ct Fancy Vivid blue diamond, square-cut, VVS1 clarity, Sotheby’s Geneva, November 2016, sold for $17,074,168 ($2,131,607 per carat).