Pink diamond auctioned for record $71.2mn in Hong Kong

Sotheby's sold a 59.6 carat pink diamond for about $71 million in Hong Kong, setting the world record for the top auction price for any gem. The stone has an unusual distinction: it has attracted even higher bids in the past.

The Pink Star sold for HK$553 million after about five minutes of bidding Tuesday. The oval-shaped diamond dethroned the Oppenheimer Blue, which fetched $58 million in May at Christie's.

In a quirk of auction history, the record price for the Pink Star is some $12 million lower than the $83 million offer Sotheby's adjudicated it for in 2013. That sale collapsed because the buyer, diamond-cutter Isaac Wolf, never paid, and Sotheby's had to reclaim the stone.

The sale gives the auction house some respite after it failed to sell other major gems last year, including the biggest rough diamond found in more than 100 years and a blue diamond ring that once belonged to Hollywood actress Shirley Temple. The Pink Star was estimated to be worth more than $60 million. It's the largest internally flawless diamond of its kind that the Gemological Institute of America has ever graded. The colour is fancy pink, the highest grade, and the purity of its crystals ranks among the top 2% in the world.

Steinmetz Diamonds, owned by Israeli billionaire Beny Steinmetz, spent two years cutting and polishing the stone, which was mined by De Beers in Botswana. The stone was then worn by Danish model Helena Christensen around her neck to exhibit it to the public for the first time in Monaco in 2003.

Pink diamonds get their colour from a process known as plastic deformation, whereby pressure changes create structural anomalies in the crystals. Sotheby's didn't change its practices for accepting bids in this auction as buyer defaults are "extremely rare," said Catherine Allen, a spokeswoman.