In the United States there is free and unlimited coinage of gold, that is, standard gold bullion may be deposited at the mints in any amount, to be coined for the benefit of the depositor, without charge for coinage; but when other than standard bullion is received for coinage a charge is made for parting, or for refining, or for copper alloy, as the case may be. Refining is the elimination from the bullion of all base metals. Parting is the separation of any silver which may be contained in the bullion. The charges for these operations vary according to the actual expenses. When copper is added for alloy, a charge of 2 cents per ounce is made for the amount actually added. The, depositor receives in gold coin the full value of the gold in his bullion, less such charges as are indicated above.

The mints may lawfully refuse to receive gold bullion of less value than $100, or when it is too base for coinage; but in practice deposits of gold bullion are accepted without regard to amounts, and rejected only when too base for coinage.