A rare 5.16-carat blue diamond sold at auction for $6.4 million in Hong Kong on Wednesday, confirming Asia’s fast-growing taste for the precious stone.

London’s famed Moussaieff Jewellers paid more than the $5.9 million expected price tag for the pear-shaped stone, the first blue diamond from the celebrated De Beers Millennium Jewels Collection to appear at auction.

The De Beers Millennium Collection, displayed in London’s Millennium Dome in 2000, comprised 12 rare gems and took decades to assemble.

“It’s a bargain and I got it at this price because everyone was asleep,” Moussaieff said in an interview.

Her London-based boutique will change the gem’s mounting and offer the stone “to discerning clients, possibly in Asia,” she said.

“The price was above the high estimate,” a spokeswoman for auction house Sotheby’s has said.

But the world per-carat record for a blue diamond remains the $10.5 M paid by a Hong Kong property tycoon for a seven-carat blue diamond in Geneva last year.

In December, a five-carat chickpea-sized vivid pink gem set a per-carat world record price for a diamond when it fetched $10.8 million at an auction in HK.

Sotheby’s said gem sales in Hong Kong were on the rise – the city has overtaken New York to become the company’s second biggest market after Geneva.