No passwords, no registration, no paywalls, no popups, no AI

As an Amazon Associate & eBay Partner we earn from affil links

finishing.com -- The Home Page of the Finishing Industry

Search our quarter-million Q&As

Home of the finishing HOTLINE since 1989

-----

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

Sorry! Finishing.com is temporarily Read-Only.
Ted Mooney is retiring but I have several offers to take it over.
We're working hard to make sure we find it the best new home.

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: