The half dollar, quarter dollar, and dime coins are clad coins with 3 layers of metal. The 2 identical outer layers are an alloy of 75 percent copper and 25 percent nickel. The inner layer is copper. The outer layers are metallurgically bonded to the inner layer and weigh at least 30 percent of the weight of the coin.
The 5-cent coin is an alloy of 75 percent copper and 25 percent nickel. In minting 5-cent coins, the Secretary shall use bars that vary not more than 2.5 percent from the percent of nickel required. Except as provided under subsection (c) of this section, the one-cent coin is an alloy of 95 percent copper and 5 percent zinc. In minting gold coins, the Secretary shall use alloys that vary not more than 0.1 percent from the percent of gold required. The specifications for alloys are by weight.