What is the purity (in karats) of the American Gold Eagle coin?

The American Gold Eagle coin is 22 karat gold.

That means its alloy is about 91.67% gold, with the balance made primarily from silver and copper. The added metals make the coin harder and more resistant to scratching than a coin made from nearly pure gold, while the stated gold content remains fixed by its weight.

The U.S. Mint introduced the American Gold Eagle in 1986 under the Gold Bullion Coin Act of 1985. It is offered in 1/10-, 1/4-, 1/2-, and 1-troy-ounce sizes, each containing its named amount of pure gold even though the coin’s gross weight is higher because of the alloy.

A common mix-up is to assume that a gold bullion coin must be 24 karat. The American Gold Buffalo is 24 karat and .9999 fine, whereas the Gold Eagle deliberately uses a durable 22-karat alloy. Its face values—$5, $10, $25, and $50—are legal denominations, not its market value, which is driven mainly by gold content.