Requirements For A Coinage Metal
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 occasionally 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).
When minting coins, especially low denomination coins, there is a risk that the value of metal within a coin is greater than the face value. This leads to the possibility of smelters taking coins and melting them down for the scrap value of the metal. Pre-1992 British pennies were made of 97% copper; but as of 2008, based on the price of copper, the value of a penny from this period is 1.5 new-pence. Modern British pennies are now made of copper-plated steel. For similar reasons, American pennies (cents) were once made of copper alloys, but since 1982 have been made of copper-clad zinc.
This problem has led to nearly the end of use for a common base metal alloy for everyday coinage in the 20th century, called Cupro-Nickel (also cupronickel), with varying proportions of copper and nickel, most commonly 75% Cu 25% Ni. 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. In the 21st century with the prices of both copper and nickel rising, it has become more common to experiment with various alloys of steel, often stainless steel. For example, in India some coins have been made from a stainless steel that contains 82% iron, 18% chromium, and many other countries that have minted coins that contain metals now worth nearly the coin face-value, are experimenting with various steel alloys.
Read more about this topic: Coinage Metals
Famous quotes containing the words coinage and/or metal:
“Designs in connection with postage stamps and coinage may be described, I think, as the silent ambassadors on national taste.”
—William Butler Yeats (1865–1939)
“And, indeed, is there not something holy about a great kitchen?... The scoured gleam of row upon row of metal vessels dangling from hooks or reposing on their shelves till needed with the air of so many chalices waiting for the celebration of the sacrament of food. And the range like an altar, yes, before which my mother bowed in perpetual homage, a fringe of sweat upon her upper lip and the fire glowing in her cheeks.”
—Angela Carter (1940–1992)