Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Black stuff inside newer pennies
Every once in a while I get a penny that is broken. Yes, actually broken not bent or cut in half. Inside is something like a black slate. It doesn't look like zinc or any sort of metal. What the heck is that?
Rich W.student - Albion, MI, United States
2004
Easy way to find out, take a file to it, see if the color is the same throughout, if so then see what it will dissolve in.
Marc Banks- Elizabeth City, North Carolina
2004
New pennies have a thin layer of copper covering a zinc core. The reason for this is because the amount of copper to make a solid penny is twice the worth of the penny itself. When zinc oxidizes, it forms black zinc oxide. If you were to scrape it off, you would see a silvery metal, zinc.
Michael Lane- Little Rock, Alabamba, United States of America
2007
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