A palladium coin is a form of currency minted from the precious metal palladium (Pt), element 46 on the periodic table. Palladium, a lustrous silver-white transition metal, is one of the six elements with similar properties making up the platinum group, along with platinum, rhodium, and ruthenium, among others. Palladium coins have been produced by a number of mints since they were first introduced by the government of Sierra Leone in 1966 and are still minted in the present day. Owing to palladium's high value, they are used as investments or commemorative items rather than for everyday commercial transactions. A privately minted palladium coin is usually called a round, as the word coin is often used to refer specifically to something produced in a government mint and recognized as legal tender.
Palladium has several attributes that make it popular for coins. Palladium is valuable because it is very rare and in demand for uses in industry, jewelry, and other areas. It is very stable chemically, like the other platinum group metals. It is soft, ductile, and has a lower melting point (2830.82 F, or 1554.9 C) than any other platinum group element, making it relatively easy to work. Palladium is one of four precious metals, along with gold, silver, and platinum, to be listed as a currency under the ISO 4217, a list of the world's currencies and their exchange rates maintained by the International Organization for Standardization. Palladium has the currency code XPD-964.
The weight of a palladium coin is usually measured in a unit called the troy ounce, which is equivalent to 480 grains or 31.1034768 grams. A troy ounce weighs approximately 9.7 percent more than the avoirdupois ounce, the unit more commonly used, along with pounds, to measure weight in countries using the Imperial or United States customary systems. No coin can be absolutely pure, but a palladium coin is commonly about 99 percent palladium.
Historically, the world's largest producer of palladium bullion coins has been the Soviet Union, and subsequently the Russian Federation after the Soviet Union's dissolution. Aside from Russia, the most prominent investment palladium coin producer is the Canadian Royal Mint, which issues the 1-ounce palladium Maple Leaf. Many other countries have produced palladium coins as commemorative items, such as the half-ounce coins minted in France in the late 1980s for the bicentennial of the French Revolution and the 1-ounce William Tell palladium coin minted in Switzerland to celebrate the 700th anniversary of the Swiss Confederation's founding.
Like other precious metals, the price of palladium varies with market conditions. Its value is generally higher than that of silver but lower than gold or platinum. Its market price temporarily rose higher than gold or platinum in 2001, when industrial demand rose sharply at the same time that production in the world's biggest palladium producer, Russia, temporarily dropped. In that year, the price peaked at $1,090 per troy ounce, or $,1340 in inflation-adjusted 2009 US Dollars (USD), before eventually falling back to more historically normal prices.