The so-called copper penny is not pure copper, and the nickel is not pure nickel!
A United States penny is 95 percent copper and five percent zinc. A nickel is three- quarters copper and only one- quarter nickel. The dime, quarter, half-dollar, and dollar coins that are minted today do not contain silver.
They are made of a copper core covered with a layer of metal containing three-quarters copper and one-quarter nickel.
