The 11.15-carat Williamson Pink Star has fetched HK$453.22 million (around US$57.73 million) at Sotheby's Hong Kong, making history as one of the most valuable diamonds ever sold at auction.

Described as one of the purest and most pink of diamonds, the cushion-shaped fancy vivid pink internally flawless diamond beat pre-sale estimates and established a price per carat record for any diamond or gemstone. 

It also become the second most valuable jewel or gemstone ever sold at auction, behind the record-breaking 59.60-carat CTF Pink Star, which generated US$71.2 million at Sotheby’s in April 2017.

Williamson Pink Star was snapped up after an intense 20-minute back-and-forth bidding battle, according to the auction house. 

A natural wonder of nature, this cushion-shaped stone was named in homage to two legendary pinks – CTF Pink Star and the Williamson – a 23.60-carat diamond given as a wedding present to Her Majesty Queen Elizabeth II in 1947 by Canadian geologist and royalist, Dr. John Thorburn Williamson, who owned the Mwadui mine in Tanzania where it was discovered. 

The discovery of a gem-quality pink diamond of any size is an extremely rare occurrence, but even more so in the past two years, with the official closure of the Argyle mine in Australia, which was responsible for the world's largest supply of pink diamonds, according to Sotheby's.