During World War II, the U.S. Mint switched to zinc-coated steel pennies to conserve copper for military use. However, a small number of 1943 pennies were mistakenly struck in copper ...

In 1943 as copper and nickel were needed by allies of the war, almost all circulating pennies were made from zinc-coated steel. But in one of the most valuable errors in coin history, some pennies ...