Page 39 - Curriculum Visions Dynamic Book

Metals for coins
A coin is a small piece of metal with marks on its surface that tell its value. Coins have little competition from
other materials. Metal coins are easily exchangeable, are small and easy to carry,
and do not readily wear out (lose their markings) or break.
Historically, people bartered with precious metals and often made them into
both jewellery and coinage. The Vikings, for example, wore armband decorations of silver and simply cut pieces off (called
hack silver) to pay their bills.
The first metal coins were issued
in the 7th century b.c. The process for making coins was to cast blank disks
using moulds into which the metal was poured. The disks were allowed
to become solid, and then they were reheated to make them soft. The marks on the surface were then hammered onto them
using a die made of a much harder metal, such as bronze or iron. In many cases iron
dies could be hard punched onto the blank. The kind of metal used depended on
what was thought of as precious. Gold and silver were common, but other metals such as iron also went into coins. Because people were used to getting something of value in exchange for their goods, the size and weight of the coins were often equal to their value as raw metal. However, as the value of these metals rose and fell, the value of the coins also rose and fell. That caused all kinds of trading problems.
To mark the fact that they were official coins, beginning with Alexander the Great, one side was stamped with images of the ruler’s head, gods, or heroes.
None of these early coins were of uniform weight or size. By the 15th century machines could be made that gave all coins the same size and weight, and so modern coins developed. The metal content of coins has also changed, although coins still
containing precious metals have
survived (mainly as special gifts) right
up to the present day (for example, golden eagles,
golden sovereigns, rands).
Ancient minting was done by placing a
blank on a die, putting another die on top of it, and then hammering the top die. That left an imprint on both surfaces. It also distorted the shape of the blank, so that many early coins have an irregular form. A die lasted for perhaps 10,000 to 20,000 coins, after which new dies had to be made.
By the Middle Ages the dies lasted much longer because they were made out of steel. The steel was then hardened by putting the die in a bed of charcoal in a sealed box, which was then put into a furnace. As the die got hot, more carbon was soaked up by the steel, making it harder.
At this time there was widespread forgery of coins – they were being made to look like a precious metal although they were made of alloys of cheaper metals.
For example, a copper coin could be
silver plated to make it look like a silver coin. Because many coins were still made
of precious metal, there also had to be a safeguard against someone filing the edge of the coins and melting down the filings. As a result, a serrated edge was put on the coins. Counterfeiting has remained a problem. However, since coins are used now only for low values, it is less bothersome.
Today blanks are no longer cast. Instead, coins are punched out of sheets of metal. Modern minting is very highly automated, with around 2,000 coins being produced by each machine each minute.
The most important issue of new coins in recent times was the production of hundreds of millions of Euro coins at the beginning of 2002, when many European countries began to use the same currency.
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