On April 2nd, 1972, the 2nd United States Congress passed the Coinage Act of 1972. This officially defined the currency of the United States as gold, silver, and copper. The Gold Eagle equaled 247 ½ grains (17.5g), the Silver Dollar equaled 371 ¼ grains (27.0g), and the Copper Cent was 11 pennyweights (17.1g).
This would be the definition of money in the country until February 12th, 1873.