Question: Is my Penny a Copper, or a Zinc Cent?
Answer:
If your Lincoln Memorial penny has a date before 1982, it is made of 95% copper. If the date is 1983 or later, it is made of 97.5% zinc, with a thin copper coating, or "clad."
For pennies minted in 1982, when both copper and zinc cents were made, the safest and best way to tell their composition is to weigh them. Copper pennies weigh 3.11 grams, whereas the zinc pennies weigh only 2.5 grams.
If you don't have a gram scale handy, you can use the "ring" test. You need a hard formica surface, a known copper penny, and a known zinc penny. Drop each one onto the table, listening to its distinctive "ring." Zinc pennies have sort of a flat ring, whereas copper pennies have a higher-pitched, more melodious "ring." Once you have a good feeling for how each type sounds, start dropping your 1982's one at a time, and you should be able to sort them out by metal composition. Obviously, this test isn't as reliable as weighing them, but it should help you sort most of them.
Cherrypicker's Tip - Watch out for "transitional" mint errors! "Transistional" errors occurred on the Lincoln Memorial Cents when the mint accidentally used copper stock for 1983 pennies. These "wrong stock" pennies weigh 3.1 grams, rather than the 2.5 of the zinc cents. If you find a copper 1983, it just might be worth... a pretty penny!More Coins Q&A