Gold and silver are the only ones regarded as precious traditional metals from the group of 4 transition metals. The value of gold and silver is very high, unlike copper which is also one of the metals belonging in the traditional transition group. Both these precious metals can stand on their own and they can be obtained without having to go through the process of metallurgy. As they are high in value and they have firm texture on their own, these characteristics have led them to be used for coinage purposes.
Gold and silver are the best precious metals for coinage purposes because they are not made of radioactive elements. They have soft texture, thus they can easily be molded into various shapes. They don’t react much when external triggers are present, and by far these two metals are the least reactive than other metals. Gold and silver have definite luster and brightness, and they make perfect jewelries and ornaments. They are not easily melted and different from other metals because their melting points are relatively higher.
Gold and silver can make great electric conductors. However, due to their high ductility ability they tend to be rather fragile and can easily tarnish. When gold and silver coins are used for circulation, then they should be able to effectively resist the impact of wear and tear. In order to meet this requirement, these precious metals need to be mixed with specific metals such as manganese. The mixing is done to make the coins become more durable and harder, so that they become more resistant towards effects of wear and tear. These metals are also alloyed so that they are not exposed to the possibilities of getting deformed.
Gold and silver coins are mainly comprised of their own components, and this means the addition of other metals into gold and silver is very little. The present 22-carat gold coins are comprised of more than 90% of gold, where the remaining percentage is comprised of copper and silver. The Canadian Maple Leaf is comprised of 99.9% gold. The U.S. minted silver coins were comprised of 90% of silver and the remaining is comprised of copper. The American Eagle is comprised of 99.9% silver and the little bit remaining percentage is comprised of copper.
When gold and silver coins are minted, there is often a risk that the value of these precious metals to be higher than the actual value of the coins. This takes effect particularly with a coin with low denomination. Due to this reason, some people have been taking advantage of this situation by melting these coins to get the gold or silver and trade them with a higher value. Copper coins are exposed to the same issue.
You can see a few instances where high density of copper is no longer used because the actual worth of the metal was not put into the practical aspect. For instance, the US pennies were once made of copper alloys but after 1982 new copper-clad zinc coins are used instead. Another example comes from the British pennies where the coins were comprised of 97% copper. These coins were lower in value compared to the actual value of the copper itself. Therefore, the new British pennies are now comprised of copper-plated steel.
Last but not least, gold and silver can be recognized as ISO4217, which is their currency code.