The U.S. Penny's Un-American History

Oct. 23, 2008 -- The exchange rate for U.S. currency abroad may have dropped to record lows in recent months, but a new study on a metal found in American minted coins suggests they are more valuable than their imprinted amounts.

The study, accepted for publication in Archaeological Science, also found that some pennies are more European than American, since the metal in them came from an English mine.

Despite the sometimes un-American history of U.S. coins, lead researcher Ryan Mathur suggested that a stash of pennies might be worth more than you think.

"At the current price of copper, it would be very profitable to melt pennies and sell the copper," he told Discovery News. "There are relatively simple calculations that demonstrate that."

The same may hold true for nickels, which consist of a copper and nickel alloy.

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For the study, Mathur, an associate professor of geology at Juniata College in Pennsylvania, collaborated with a museum director, another geologist, a coin dealer and other experts to analyze U.S. currency coined from 1828 to 1972.

They determined that while copper in U.S. coins does not carry a distinct signature, copper isotopes do vary depending on the temperature at the time of mineralization. This allowed them to trace metal sources back to their original ore deposits. An isotope is one of two or more atoms that have the same atomic number but different mass.

Historical records reveal that from 1800 to 1837, entrepreneur Matthew Robinson Boulton, who was director of the Soho Mint in Cornwall, England, supplied copper for the U.S. Mint. Mathur and his team, however, could see that British copper remained in American cents until 1849, when the supply came from a Michigan mine.