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If copper turns green when its left out why aren't pennies green?

Tori Carter
- Portsmouth, Ohio


The answer would either have to be that they are not copper or they are not left out, huh?

Tell your parents they have to take you to a beach with a boardwalk if they care about your education. Walk the boardwalk until you find a couple of pennies lying on the support beams between the cracks. They'll be there (you may have to spend the whole weekend at the beach, but a good education is vital). Take these green pennies into school for your science project.

Pennies that are handled don't go green because the green coating is not wear resistant like the brown coating. Good luck.

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey


My name is Courtney!
I'm doing a project for fun and I want to know what pennines are made of and what minerals are in it. Also, how do you clean a penny? I learned how to make it look old and new but how about what minerals are in it that make it dirty and old, rusty.

student - Poughquag, New York, New York


Do some homework for yourself. For a start, do a search of the letters at this site. The questions come up literally dozens of time each year, and that is only the published ones. If you can find this site, you can find at least the first part of your question. Mineral means a solid to most of us. Solids will not normally react with a metal, so what might the missing part be? PS, I do not consider mercury to be a mineral.

James Watts
- Navarre, Florida


Hi Courtney,

You can learn all you want to about pennies by going to the US Mint website. As for what minerals are in the penny that make it look old, they are (with the exception of embedded dirt) corrosion products of the metal from the penny and other chemicals - namely oxygen and (I'm not 100% certain on this) sulphur.

If you use the search engine on this website you'll find lots of letters discussing pennies and various cool things you can do to them, as well as a few that go into deeper detail than I have.

Have fun!

Jim Gorsich
Accurate Anodizing Inc.
supporting advertiser
Compton, California, USA
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