1851–1873 Half dime: 5¢, 1792–1873 Twenty-cent piece: 20¢, 1875–1878 Gold dollar: $1.00, 1849–1889 (some early commemoratives were minted in this denomination) Quarter eagle: $2.50, 1792–1929 (some early commemoratives were minted in this denomination) Three-dollar piece: $3.00, 1854–1889 Stella: $4.00, 1879–1880 (not circulated) Half eagle: $5.00, 1795–1929 (some modern commemoratives are minted in this denomination) Eagle: $10.00, 1795–1933 (some modern commemoratives are minted in this denomination) Double eagle: $20.00, 1849–1933 Half-union: $50.00, 1877 (not circulated, some early commemoratives were minted in this denomination) Union: $100.00 (planned but not minted, some modern commemoratives are minted in this denomination) The law governing obsolete, mutilated, and worn coins and currency, including types which are no longer in production (e.g. Indian cents), can be found in . Note: It is a common misconception that "eagle"-based nomenclature for gold U.S. coinage was merely slang. The "eagle," "half-eagle" and "quarter-eagle" were specifically given these names in the Coinage Act of 1792. Likewise, the double eagle was specifically created as such by name ("An Act to authorize the Coinage of Gold Dollars and Double Eagles", title and section 1, March 3, 1849). Mill coins Although the term mill (also mil or mille) was defined in the eighteenth century as of a dollar or 0.1¢, no coin smaller than 0.5¢ has ever been officially minted in the U.S. However, unofficial mill coins, also called "tenth cent" or "tax-help coins", made of diverse materials—plastic, wood, tin, and others—were produced as late as the 1960s by some states, localities, and private businesses for tax payments and to render change for small purchases. Legal protections The alteration or lightening of U.S. coins for fraudulent purposes is illegal. It is generally legal to melt down coins for the use of their constitent metals, but the Treasury Department has occasionally prohibited melting down and mass exportation when the value of the metal exceeds the face value of the coin. This has happened from 1967 to 1969 for silver coins, from 1974 to 1978 for pennies, and since 2006 for pennies and nickels. The use of elongated coin presses is considered legal because it is not for fraudulent purposes. See also 50 State Quarters California gold coinage Federal Reserve Note, for U.S. banknotes United States Mint coin sizes Penny debate in the United States Modern United States commemorative coins United States commemorative coin United States coinage type set Notes References External links of the United