A coin is usually a piece of hard material, usually metal or a metallic material, usually in the shape of a disc, and most often issued by a government. Coins are used as a form of money in transactions of various kinds, from the everyday circulation coins to the storage of vast amounts of bullion coins. In the present day, coins and banknotes make up the cash forms of all modern money systems. Coins made for circulation (general monetized use) are usually used for lower-valued units, and banknotes for the higher values; also, in most money systems, the highest value coin is worth less than the lowest-value note. The face value of circulation coins is usually higher than the gross value of the metal used in making them, but this is no longer generally the case with historical circulation coins made of precious metals. For example, the historical eagle ( United Statues coin ) contained .48375 troy ounce of gold and has a face value of only ten U.S. dollars, but the market value of the coin, due to its metal content, is now many times the face amount.
