Whenever
any commodity is used for the exchange purpose, the commodity becomes
equivalent to the Money and is called commodity money. For example: if a silk merchant buys rice from the farmer,
he pays the farmer with silk. Commodities that have been
used as medium of exchange include gold, silver, copper, salt tea,
large stones shells, alcohol, cigarettes, silk, cocoa
beans, cowries and barley
etc. Commodity money were generally used in the barter exchange system. The
main drawbacks of commodity money are: lack of store of value & lack of
common measure of value & need of double coincidence of wants. For the centuries
commodity exchange system was being used by many civilizations, due to the
introduction of metallic coins as a medium of exchange, it is not used in
modern currency system.