Gold American Eagle Proof Set
American gold eagles were introduced in 1986 and have been struck every year since. In the inaugural year only the one ounce and half-ounce denominations were offered in the Proof format. Starting in the 1987, all four denominations, comprising the $50 one ounce, $25 half-ounce, $10 quarter-ounce and $5 tenth-ounce pieces were issued as Proofs. The denominations are offered by the Mint in sets of four and individually. As a method of collecting, and a way to accumulate gold, many numismatists assemble sets of each denomination by date. Reference books on American gold eagles include A GUIDE BOOK OF UNITED STATES COINS by R.S.Yeoman.