<P> In situations where the commodity is metal, typically gold or silver, a government mint will often coin money by placing a mark on the metal that serves as a guarantee of the weight and purity of the metal . In doing so, the government will often impose a fee which is known as seigniorage . </P> <P> The role of a mint and of coin differs between commodity money and fiat money . In situations where there is commodity money, the coin retains its value if it is melted and physically altered, while in a fiat money it does not . Usually in a fiat money the value drops if the coin is converted to metal, but in a few cases the value of metals in fiat moneys have been allowed to rise to values larger than the face value of the coin . In India, for example fiat Rupees disappeared from the market after 2007 when their content of stainless steel became larger than the fiat or face value of the coins . In the US, the metal in pennies (97.5% zinc since 1982, 95% copper in 1982 and before) and nickels (75% copper, 25% nickel) has a value close to, and sometimes exceeding, the fiat face value of the coin . </P> <P> Commodities often come into being in situations where other forms of money are not available or not trusted . Various commodities were used in pre-Revolutionary America including wampum, maize, iron nails, beaver pelts, and tobacco . According to economist Murray Rothbard: </P> <P> In the sparsely settled American colonies, money, as it always does, arose in the market as a useful and scarce commodity and began to serve as a general medium of exchange . Thus, beaver fur and wampum were used as money in the north for exchanges with the Indians, and fish and corn also served as money . Rice was used as money in South Carolina, and the most widespread use of commodity money was tobacco, which served as money in Virginia . The pound - of - tobacco was the currency unit in Virginia, with warehouse receipts in tobacco circulating as money backed 100 percent by the tobacco in the warehouse . </P>

Camels have been used as money. which function of money would this type of money perform least well