Your penny is from a grease filled die. It's a common occurence, so no extra value. Except for war nickels, nickels are made from an alloy of 75% copper and 25% nickel. Your "copper" nickel is probably just damaged, but a picture would go a long way in determining anything more. BTW, welcome to CT! Just a warning, you'll be chewed up by some for your use of the word penny. Please don't let the Numismatist Nazis here put you off.
Grease-filled dies are as common as dirt, but look at the bright side. If you find 100 million of them, you'll be a millionaire. Chris
