OTTAWA (Reuters) — Investors are taking a shine to a rare, silvery-white metal called molybdenum, but the durability of a market rally may hinge on looming export controls from China.A surge in prices could benefit producers and the Toronto Stock Exchange, home to the world’s largest publicly traded, pure-play molybdenum producer, Blue Pearl Mining, and a host of explorers.

Stocks related to the base metal, valued for its anti-corrosive and strengthening properties, have been soaring for weeks, underpinned by sturdy prices and buzz about a new fund that will invest in molybdenum and the companies that produce it.

Now, anticipation is building for news on a quota system from China, which could soon release a list of the molybdenum producers it will allow to export. Fewer than 30 names are expected, a Chinese industry group said, and exports could fall by 10 percent.

“It comes down to the Chinese,” said Ian Nakamoto, director of research at MacDougall, MacDougall & MacTier. “They could make or break the market.”

About 400 million pounds of molybdenum were produced last year, with tight supplies making the market sensitive to supply disruptions and contributing to price pressures.

China is a major supplier of the metal, used primarily as a hardening agent in the production of stainless steel. The tough-to-pronounce metal moved into the mainstream amid a meteoric rise for shares in Toronto-based Blue Pearl.