There are a lot of gold coins out there and one of the most popular is the American eagle gold bullion coin. This gold is one of America's official investment grades. The content, purity and weight of the American eagle gold bullion is guaranteed by the United States government.The coin is 22 karats, since gold is a soft metal they decided to put a mixture of silver and copper to strengthen the coin and keep them looking new. That is why the coin has only 22 parts gold and the other 2 part are silver and copper.