Commodity money as a theoretical backing for federally issued "gold certificates" to substitute for the gold. Between 1933 and 1970 (when the U.S. officially left the gold standard), one U.S. dollar was technically worth exactly 1/35 of a troy ounce (889 mg) of gold. However, actual trade in gold bullion as a precious metal within the United States was banned after 1933, with the explicit purpose of preventing the "hoarding" of private gold during an economic depression period in which maximal circulation of money was desired by influential economists. This was a fairly typical transition from commodity to representative to fiat money,
Commodity money modern commodity markets, although they use a sophisticated range of financial instruments that are more than one-to-one representations of units of a given type of commodity. Since payment by commodity generally provides a useful good, commodity money is similar to barter, but is distinguishable from it in having a single recognized unit of exchange. described the establishment of commodity money in P.O.W camps. Radford documented the way that this 'cigarette currency' was subject to Gresham's law, inflation, and especially deflation. In another example, in US prisons, after smoking was banned circa 2003, commodity money has switched in many places to