A 15.38-carat vivid pink diamond, the biggest of its kind to go on auction, was sold for a new record total of $31.56 million (27.88 million euros), Sotheby’s auction house said Tuesday. “It’s a new world record… It’s the highest price ever paid for a fancy vivid pink diamond,” said auctioneer David Bennett. The stone with the name “Unique Pink” was certified a fancy vivid pink diamond, the most sought after colour in pink diamonds, by the Gemmological Institute of America.