Coins are made from one or more
coinage metals.
Many coinage metals are from Group 11 of the Periodic table, however there are some exceptions. Precious metals are used in bullion coins and some collectable coins. Coins not intended for circulation or for intrinsic value, have also been made experimentally using an even larger variety of metals, in technical and artistic experiments.
Coins that are intended for circulation have some special requirements based on the conditions they will encounter. For example, a coin may be in circulation for up to 30 years, and so must have excellent wear resistance and anti-corrosion properties. Achieving this goal necessitates the use of base metal alloys. Some metals like manganese have occassionaly been used in coins, but suffer from making the coins too hard to take an impression well (or metals apt to wear out stamping machines at the mint).
A common base metal alloy for everyday coinage is Cupro-Nickel (also cupronickel), with varying proportions of copper and nickel. Cupronickel has a silver color, is hard wearing and has excellent striking properties, essential for the design of the coin to be pressed accurately and quickly during manufacture.
