In 2006, the U.S. Mint released its first 24-karat (.9999 gold) gold bullion coin, the American Buffalo. The initial sets, both uncirculated and proofs, were only made in 1 oz versions, with a face value of $50, but the mint sold the coins for $800 each, which reflected the value of their gold content at the time.

The reason the United States decided it needed such a fine coin when it already had four denominations of 22-karat American Eagles is that it felt the need to compete with other countries that printed pure gold coins—in particular Canada, which had been very successful with its Canadian Maple Leaf coin.

The American Buffalo’s design pays homage to James Earle Fraser's Buffalo (Indian Head) nickel. The Buffalo nickel was the American five-cent piece from 1913 until 1938, with the exception of a few years during which no nickels were minted. The obverse depicts the profile of a Native American while the reverse shows a bison atop a mound of dirt. Unlike the Buffalo nickel, however, the legend under the gold bison’s feet reads “$50 1 OZ. .9999 FINE” instead of “FIVE CENTS.”...