13 Aluminum (Al)

atomic weight 26.98, melting point 660° C, density 2.70 g/cc

Aluminum is commonly used worldwide for low-value coins, tokens, and art medallions. It's soft, so it doesn't wear well, but it does have the advantage of acquiring a thin transparent layer of oxidation which helps protect coins from further corrosion. Here is a particularly attractive, common, and fairly large French 5 franc piece.

More than once, the price of copper has risen to the point where a cent cost the United States more than a cent to make. Alternatives have been proposed, including aluminum, but since mid-1982 the solution has been to make cents out of copper-plated zinc. Some aluminum trial Lincoln cents were produced in 1974. They were supposed to be destroyed, but a few escaped the Mint. Now they are worth a fortune.

Ironically, aluminum at one time was worth more than gold! The Deville method for isolating aluminum, perfected in 1854, could only produce small lumps at high cost. By 1866 Hall and Heroult had figured out how to use electric current to separate alumina, driving the cost down to around that of silver. In 1888 they were producing ingots using hydroelectricity from Niagra Falls, and by 1893 the price of aluminum was down to about 65 cents per pound.

Aluminum medal by Metallium, Inc. Photo used by permission.
Diameter 19 mm, 1.1 grams, 99% pure. $6 on 6/9/2006