Silver is in such demand in commodities markets these days that mints are rationing their sales of the coins they make, the Financial Times reports.

Silver prices hit $31.37 a troy ounce recently, their highest levels since March of 1980.

Mints rationing some sales include the Royal Canadian Mint and the Austrian Mint.

Some mints ration silver-coin sales.

"We have sold everything we can produce in silver and have demand for at least twice that volume," says David Madge, head of bullion sales at the Royal Canadian Mint, which produces the silver Maple Leaf coin.

The Austrian Mint sold 1.53 million ounces of its silver Philharmonic coin in January, more than double what it moved a year earlier.

“We could have sold more,” Andrea Lang, the mint's marketing director, tells the Financial Times, adding that the mint would boost production to 2.2 million ounces for February and March.

Weaker currencies around the world have fueled demand for metals as hedge investments, especially gold and silver.

Silver has more industrial uses than gold, and an improving economy is increasing silver's need even further.

For those investors who believe the that the economy will improve even more, "fundamentally silver probably has better reasons to rally than gold," Frank Cholly, a senior market strategist at commodities trader Lind-Waldock in Chicago, tells the Los Angeles Times.

Others agree.

"Silver will outperform gold because of its industrial uses, together with the fact that the number of potential investors is far greater," says Julian Phillips, an editor at SilverForecaster.com and GoldForecaster.com, according to Market Watch.