Hong Kong, China: Sotheby's said it would auction a rare 5.16-carat blue diamond in Hong Kong to capitalise on the growing appetite for fine jewellery among buyers in China and other Asian countries.

The auction house said the pear-shaped blue diamond from a private collector was expected to fetch up to US$5.8 million ($8.15 million) at its April sale in Hong Kong, which now rivals Geneva and New York as an international auction hub for rare gemstones.

Sotheby's said its Hong Kong share of international jewellery sales jumped from 19 percent in 1998 to 34 percent in 2008, overtaking New York to be its second biggest market after Geneva.

Terry Chu, deputy head of Sotheby's jewellery department for China and Southeast Asia, said diamonds were particularly appealing to new Asian buyers because of stable prices and assured quality.

"There have been a lot of new diamond buyers from mainland China, Hong Kong, Singapore, Taiwan and elsewhere in the region," Chu told AFP.

"I think after the financial crisis, the Asian buyers realised that the prices of diamond are relatively stable compared to other types of auction items," she said.

In December, a five-carat chickpea-sized vivid pink diamond set a per-carat world record price for a diamond after it fetched US$10.8 million at an auction held by Christie's in Hong Kong.

The price beat a Hong Kong property tycoon's US$10.5 million winning bid for a seven-carat blue diamond in Geneva in May last year.

Both Sotheby's and Christie's said last year that the city had overtaken New York and London as the largest wine market, spurred by China's economic boom and a rapidly growing demand from deep-pocketed Chinese businessmen for top wine.