1990 1 oz $50 USD American Proof Gold Eagle (In capsule) Year: 1990 Grade: Proof Country: United States Denomination: $50 USD Metal Content: 1 troy oz Purity: .9167 Fine Gold Proof Gold Eagle coins are collector versions of the U.S. Mint's beloved Gold Eagle bullion coins and have limited mintages, adding to their collectibility. Typically, Proof coins are struck two or more times, producing a very high degree of detail.