'Ultra-rare' pink diamond expected to sell for more than $35 million at auction

pink diamond of "unparalleled color and brightness" is expected to fetch over $35 million when it goes on sale in New York, auction house Sotheby's announced Wednesday.

Weighing 10.57 carats and named The Eternal Pink, the "ultra-rare" gemstone will go under the hammer this June, four years after South African firm De Beers discovered it at one of its mines in Botswana.

Officially classed as "purplish pink" in color, it is the most valuable diamond of its shade ever to appear at auction, according to Sotheby's. The auction house's head of jewelry for the Americas, Quig Bruning, said in a statement that the stone was "joining the ranks of the most important diamonds in history."

The price of diamonds is largely determined by what gemology experts call the four "Cs": carat, cut, color and clarity. For the latter grading, the stone has been classed as "internally flawless," meaning any blemishes are only visible under close magnification. Its color has meanwhile been designated "fancy vivid," the highest grade of intense color achieved by only 4% of pink diamonds.

"This color is the most beautiful and concentrated shade of pink in diamonds that I have ever seen or has ever come to market," Bruning said, adding: "The Eternal Pink's immense presence and great rarity make it comparable to ultimate masterpieces of art — far rarer than a Magritte or a Warhol."

Pink diamonds have soared in value in recent years. This is due, in part, to a slump in supply caused by the 2020 closure of Australia's Argyle Mine, which previously produced most the world's pink diamonds. According to an index compiled by brokerage Australian Diamond Portfolio, the average price of the colored stones jumped 30% in just the 12 months before June 2021.

The Eternal Pink was cut from a rough diamond, discovered in 2019, that at 23.87 carats weighed more than twice as much as it does now. It took diamond firm Diacore six months to transform the stone into its current form.

Less than 3% of diamonds submitted to the Gemological Institute of America (GIA) are colored, with pink ones among the rarest, Sotheby's said. In the auction house's press release, the GIA's executive vice president Tom Moses called the Eternal Pink a "stunning specimen," adding that its "refined lines combined with the intensity of its color earn it a place as one of the world's most extraordinary gems."

The stone will be unveiled in Hong Kong on Saturday. It will then be exhibited in several cities, including Dubai, Singapore and Geneva, before heading to New York for June's sale.

The auction record for a pink diamond — or a polished diamond of any color — is currently held by a 59.6-carat stone that sold for $71.2 million at Sotheby's Hong Kong in 2017. The pink diamond was purchased by Hong Kong jewelers Chow Tai Fook and renamed "CTF Pink Star."

A 11.15 carat pink diamond dubbed "Williamson Pink Star" meanwhile holds the record for the highest per-carat auction price, after it sold for 453.2 million Hong Kong dollars ($58 million) last year.