11.5-Carat Rosenberg Williamson Pink Star Diamond Fetches $57.7 Million, A World Record Price

In an auction that ended moments ago, the 11.5-carat Williamson Pink Star diamond sold for approximately $57.7 million (including the auction premium) at Sotheby’s Hong Kong. Its per carat price of more than $5 million shattered the previous auction record. It is the second most valuable jewel or gemstone ever sold at auction.

It took approximately 20 agonizing minutes for the second largest internally flawless fancy vivid pink diamond to ever appear at auction to be sold in a stand-alone sale, as seen through Sotheby’s live stream.

The gem was sold to a collector in Boca Raton, Fla., and renamed the Rosenberg Williamson Pink Star.

There were several people bidding on the diamond at the Hong Kong Convention and Exhibition Centre where the auction was held and by phone. Actioner Ian McGinlay opened the bidding at HKD$140 million and slowly rose to HKD$165 million. Longer pauses on the bids started at HKD$200 million. Bidding was reduced to one person in the room and two phone bidders. Bidding proceeded slowly in increments of HKD5 million until it reached HKD300 million, followed by applause. But still bidding continued among the three participants. Once bids reaching an astounding hammer price of HKD$392 million ($50 million) to the room bidder, the auction closed to applause. The final price includes the buyers’ premium.

The previous price per carat auction record for a fancy vivid pink diamond was $2,656,909 for the 18.96-carat Winston Pink Legacy, sold in 2018.

Wenhao Yu, chairman of Jewellery and Watches at Sotheby’s Asia, told Forbes prior to the sale that the cushion-shaped diamond “has the best qualities you can have in a pink diamond.” He also compared the diamond to an exceptional work of art, which is why it was offered between Sotheby’s Hong Kong modern and contemporary art auctions.

The diamond was named after the Williamson Mine in Tanzania, where it was unearthed. It is one of the oldest operating diamond mines in the world, famous for producing what is described as “bubblegum pink” diamonds, according to the auction house. One of the best-known diamonds from the mine is the 23.6-carat Williamson Pink Diamond fashioned into a brooch by Cartier and owned by Queen Elizabeth II.

The Williamson Pink Star was crafted from a 32.32-carat rough diamond by Diacore, a diamond manufacturer that specializes in crafting rare, exceptional fancy-colored diamonds. The company purchased the gem in late 2021 for $13.8 million. Yu says crafting the diamond is just as important as discovering it, and Diacore is one of the few companies in the world capable of cutting and polishing such an important gem.

“It’s luck to find this kind of diamond that was formed underground for millions of years, and it takes a great amount of art and creativity to fashion it into a gorgeous stone with so many exceptional qualities,” Yu said.

Pink diamonds are among the rarest colors to occur naturally in diamonds. Of all the diamonds submitted to the Gemological Institute of America (which analyzes and grades diamonds), fewer than 3% are classified as colored diamonds, and fewer than 5% of those are considered predominantly pink.

The Argyle Mine in Australia, before it was retired in 2020 after exhausting its supply of gem-quality diamonds, produced more than 90% of the world’s pink diamonds. The absence of pink diamonds from this mine makes important pink diamonds like the one being offered even more rare, Yu says.

The diamond was sold on an 18k gold ring flanked by trapeze-cut diamonds and embellished with brilliant-cut diamonds.

The largest internally flawless, fancy vivid pink diamond ever offered at auction is the 59.60-carat CTF Pink Star, which was sold by Sotheby’s Hong Kong in 2017 for $71.2 million, a world record for any gem or jewel sold at auction.