The link below give the specifications of all current U.S. coins.
Apparently coins are made out of Iron, Metal, Bronze and other of types of metals/brass.
Today in currently circulating coins produced in 2013 there are a number of different metals used. Copper and nickel are used for the nickel, dime, quarter and half dollar. Copper plated zinc is used for the penny and a special alloy of brass is used for the dollar coin. However, silver, gold and platinum are used for commemorative and bullion coins which do not circulate.
Silver
Copper
Coins are found by the detector sending a pulse which picks up metal signals. Now there are two types a low frequency and a pulse indicator, the low frequency is used to pick up deeper objects
The metal used for low value coins is typically copper or a combination of copper and other metals like zinc.
You can classify coins based on properties such as size, weight, shape, composition (metal used), denomination value, year of minting, and design elements. These properties can help differentiate and categorize coins into various types or series.
Silver is a type of metal. It is used for jewelry, utensils, coins, and much, much more!
It is used as a metal, and it is used in the coins we use today.
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While it is now never used in currency, the metal silver is used in jewellery and photography.
Metals used in Indian coins are nickel, copper, stainless steel, aluminium.