Coins in the United States are made of various metals, with most being a composite of several metals and alloys. Depending on the type of coin, metals as of 2014 include copper, copper-plated zinc and combinations of nickel, according to the United States Mint. The composition of coins has changed over the years due to manufacturing costs and other considerations.
The United States Mint provides specific information on each coin. Quarters and dimes are composed of the same materials, which are cupro-nickel clad, with a pure copper core and an outer layer made of 75 percent copper and 25 percent nickel alloy. Nickels have a 75-25 alloy combination overall. The cent, commonly referred to as a penny, is composed of copper-plated zinc.
The cent was previously made from 95 percent copper and 5 percent zinc, but the switch to majority zinc lowers the cost of manufacturing and creates a coin that weighs about 20 percent less, according to the United States Mint. Pennies now weigh 2.5 grams each instead of the previous 3.11 grams.
According to Coin Spot, dimes, quarters and half-dollars in the United States were made from silver until 1964 when the price of the metal escalated and the government switched to a nickel alloy. Coins made of pure silver or gold are now highly collectible items.