Hong Kong jewelry collector Dennis Sun has been buying jade for three decades. Lately, it has been harder to snag the perfect piece as mainland Chinese buyers drive prices through the roof.

At a Christie’s auction in May, he watched a jadeite ring sell for about HK$20 million ($2.6 million), or five times its estimated price. Last month, he bought a jade bangle for almost HK$1 million even though the color and quality weren’t all had hoped for.

“The prices went up so high, if I don’t buy it now it’ll only get more expensive later,” he said.

The value of the precious gem is surging with China’s wealthy snapping up jade necklaces, rings and bracelets as long- term investments. They are counting on the stone’s steady ascent to provide safety as Shanghai’s stock market languishes, much of the bond market remains closed to retail investors and even gold prices have plunged.

About 90 percent of the world’s jadeite, the most precious version of the stone, comes from mines in Myanmar. Prices are surging because demand is outpacing supply, said Humphrey Yen, an instructor at the Hong Kong Institute of Gemmology.

Even so, buyers “may find it hard to cash out as there is a lack of an internationally recognized market or a price standard for the gemstone,” Yen said.

Bidding Wars

Without standard international pricing systems, buyers and sellers rely on subjective valuations by jewelry experts, or use auction bids as a gauge.

“They will have to rely on auction houses to facilitate a trade, or trade it between collectors,” said Yen. “Otherwise, they need to establish connections to jewelers.”

Best known as a green gem, jade comes in colors such as red, yellow, white and lavender. Its price has doubled at auctions over the past five years with more than half of Sotheby’s recent jadeite sales coming from Chinese buyers, said Terry Chu, deputy head of Sotheby’s jewelry department in Asia.