ZURICH – Hong Kong-based jewelry retailer Chow Tai Fook bought a 59.6 ct pink diamond for about $71-million, 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 jeweler made the HK$553-million winning bid for the Pink Star, ending a five-minute contest that included three phone bidders, Sotheby’s said 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 the auction house had to reclaim the stone.

Chow Tai Fook’s purchase gives Sotheby’s 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.

Chow Tai Fook, founded in 1929, is the world’s largest jeweler, operating more than 2 000 jewelry and watch stores throughout greater China. This isn’t its first purchase of the kind: last year it bought a green diamond for $17-million at a Christie’s auction, and in 2010 the jeweler set a record with its $35-million purchase of a rough diamond from Cullinan. In 2015, Chow Tai Fook unveiled a necklace made with 24 gems cut from that 507 ct stone.

More recently, the chain has been targeting younger shoppers with collectible gold Star Wars figures and diamond-encrusted Mickey Mouse pendants.

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 color 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 color 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 spokesperson.