The 1oz Gold American Buffalo Coins are the first .9999 fine (24 karat) struck by the U.S. mint. Production of 24-karat American Buffalo Gold Coins was authorized by Public Law 109-145, dated December 22, 2005, known as the Presidential $1 Coin Act.
Many folks don’t know this, but during World War II, for one year only, the United States minted the 1943 Steel Penny. The 1943 silver colored penny is a wartime issue made of steel, and coated with zinc. During World War II, copper was so badly needed for the war effort (to make shell casings) that the U.S. penny was made out of steel that year, which is why most 1943 pennies are silver colored.