The Williamson Pink Star, shown here in an undated photo from Sotheby's, was auctioned off at $49.9 million in Hong Kong on Friday, Oct. 7, 2022, setting a world record for the highest price per carat for a diamond sold at auction.

Pink diamond auctioned at $57.73 million, most ever per carat

A pink diamond closed at auction for $57.73 million in Hong Kong Friday night, the most expensive diamond per carat ever sold.  The 11.15-carat Williamson Pink Star diamond sold at a Sotheby’s auction. The $57.73 million price tag includes the auctioneer’s fees. Without the fees, the raw price of the diamond is $49.9 million, or…