I would appreciate some help on this one. Tried searching but haven't found out weather these are a possibility or not. Thanks
Environmental Damage Here are some I found Metal Detecting. Now you know what happened and that your Nickel is not a Mint Error..
Nickels are made of 25% nickel and 75% copper. If you see on your coin, it looks like it is dirty and has some garbage there that would make it appear a light green in some areas. If you ever come across (which I have not) a coin that has a missing clad layer, you will more than likely know it. Google any denomination with missing clad layer and study those photos. @paddyman98 gave you a good selection that showcase environmental damage. Study the google photos and paddy's and you should be able to determine the difference while you are searching. Have fun!!
I wasn't very clear in that I thought the OP was wondering if they had a missing clad layer. They did ask if it was copper so I did explain that it was 75% copper. I did not state it was alloyed. My apologies.