World's Most Popular Gold Coins. American Eagle gold coins were first issued in 1986 by the U.S. Mint and quickly became one of the leading gold bullion coin investments. Minted in 22 Karat Solid Gold, American Eagles use the durable gold standard established for gold coins circulating over 350 years ago. Each of these gold coins is minted in 91.67% fine gold, creating a harder coin that resists scratching and marring.