Jack O writes: In the compositions you provide for US gold coins both before and after the change from 91.7% to 90% fine (in 1838??), you give them all as gold + copper. I read somewhere once that, like the UK gold Sovereign coin, the earlier US gold issues were actually gold+silver and/or gold+silver+copper. Does this ring any bells, and if so do you know the relevant dates? A million thanks.
Early U.S. gold coins (1795-1834) consisted of a composition of .9167 gold and .0833 silver and copper. From 1834-1837 the composition was .8992 gold and .1008 silver and copper. In 1837 gold coin composition was changed to .900 gold and .100 copper and that formula continued until the cessation of gold coinage in 1933.
Modern U.S. commemorative gold Eagles and Half Eagles, commencing with the 1984 Olympic $10 and the 1986 Statue of Liberty $5, continue the .900 gold, .100 copper composition of the earlier coins.
American Eagle gold bullion and proof coins are composed of .9167 gold, .03 silver and .0533 copper. The American Buffalo gold bullion and proof coins are .9999 fine gold as are the First Spouse series of $10 gold coins. The 2009 (MMIX) version of the Ultra High Relief $20 coin is .999 fine gold.
