A platinum coin is a type of currency made from the chemical element platinum, a precious metal. Some platinum coins are legal tender in their country of origin, but due to the high value of platinum they are primarily used as a means of investment rather than for normal cash transactions, and their face value as legal tender is usually much lower than the actual value of the metal. Platinum metal bullion coins are usually bought and sold at higher prices than an equal weight of unminted platinum due to the cost of their production, the value of the mint's stamp as a certification of the coin's purity, and, in some cases, their value as collectibles. Platinum bullion coins are produced by a number of government mints, including the United States Mint, the Royal Canadian Mint, and the Royal Mint of the United Kingdom. Privately owned mints also produce platinum coins, which are often called rounds to distinguish them from government-minted coins.
Platinum is a gray-white transition metal with an atomic number of 78 and has a number of qualities that make it useful as a currency. It is the most prominent member of a group of valuable metals called the platinum group, which also includes the precious metal palladium and the two densest elements on the periodic table, osmium and iridium. Platinum is extremely rare and highly valuable due to its use in areas such as jewelry, electronic components, and medicine. Platinum is also very stable, making a platinum coin especially resistant to corrosion and other chemical reactions and suitable as a long-term store of value.
The weight of a platinum coin is measured in troy ounces, a unit equal to 480 grains or 31.1034768 grams. The most common weight for a platinum coin is one troy ounce, and fractions such as one-half, one-fourth, and one-20th of an ounce are also common. The price of platinum varies according to economic conditions and can be quite volatile, sometimes rising significantly higher than the price of gold and sometimes falling below it. Along with gold, silver, and palladium, platinum is one of the four precious metals included by the International Organization for Standardization on the ISO 4217, a listing of world currencies and their values used in banking and international business. Platinum is listed with the alphabetic code code XPT and the numeric code 962.
The first government to produce a platinum coin was the Russian Empire, which minted the coins from 1828 to 1845. Modern platinum bullion coins include the Canadian platinum maple leaf, the American platinum eagle, and the Australian platinum koala. Many nations have minted commemorative platinum coins to mark special occasions such as historical anniversaries or prestigious events such as the Olympic Games or to honor national heroes and achievements. Examples include platinum coins issued by the Royal Mint of the United Kingdom for the wedding of Prince Charles and Lady Diana Spencer, the 200th anniversary of Admiral Horatio Nelson's death at the Battle of Trafalgar, and the 500th anniversary of the coronation of King Henry VIII. The Soviet Union produced a number of commemorative platinum coins, including the coins issued by the Soviet Union commemorating the 1980 Summer Olympics in Moscow and a platinum coin commemorating the 500th anniversary of the standoff between the Russian and Mongol-Tatar armies at the Ugra River in 1480.