11.28-Carat 'Infinite Blue' Could Sell for $37MM at Single-Lot Sotheby's Auction

The 11.28-carat "Infinite Blue" is about to punch its ticket to the pantheon of the greatest blue diamonds of all time. Sotheby's Hong Kong will be auctioning the cut-cornered rectangular mixed-cut Fancy Vivid Blue stunner at a special single-lot event on October 5.

The gem, which is set in a ring with a pink diamond halo and trapezoid-cut white diamond side stones, comes with a pre-sale estimate of $26 million to $37 million. The high estimate translates to $3.3 million per carat.

The Infinite Blue can track its lineage to Petra Diamonds' iconic Cullinan Mine in South Africa, which has produced more than 800 stones weighing more than 100 carats and is renowned as the world’s most important source of blue diamonds.

Blue diamonds the size and quality of the Infinite Blue are exceptionally rare. It is believed that only six examples weighing more than 10 carats have ever come to auction.

In April 2022, the 15.10-carat “De Beers Blue” was within a whisker of setting a new world record for the priciest vivid blue diamond ever sold at auction. The hammer price of $57.47 million ($3.8 million per carat) at Sotheby’s Hong Kong was just short of the $57.54 million ($3.9 million per carat) achieved by the 14.62-carat “Oppenheimer Blue” at Christie’s Geneva in 2016.

Back in 2015, “The Blue Moon of Josephine,” a 12.03-carat internally flawless fancy vivid blue diamond, sold for $48.5 million ($4 million per carat) at Sotheby's Geneva. Earlier this year, the “Bulgari Laguna Blu,” an 11.16-carat fancy vivid blue diamond, fetched $25.2 million ($2.3 million per carat), also at Sotheby’s Geneva.

A Gemological Institute of America Monograph described the quality and rarity of the Infinite Blue. The GIA wrote, “To say the Infinite Blue is special cannot be overstated. The odds of finding a blue diamond is of the topmost rarity. This glorious and notable diamond is an example of what can occur when nature leads the way, and humankind embraces the earth’s treasures—producing a radiant gem of spirited light performance. The Infinite Blue will continue to stun gem connoisseurs and diamond lovers alike. In the world of gems, blue diamonds steal the show.”

Blue diamonds are considered one of the rarest colors of all diamonds. A fabulous fluke of nature, a blue diamond owes its color to the random presence of boron within the diamond’s carbon structure. The Infinite Blue is categorized as a Type IIb diamond, a quality level that includes less than 0.5% of all diamonds.

Scientists believe that blue diamonds form about 400 miles below the surface, four times deeper than about 99 percent of all other diamonds.

Credit: Image via Instagram / sothebysjewels.