Taz a quarter or 50 cent coin has probably bumped into it. this looks like where the reeded edge of another coin has damaged you nickel.
Taz I swear some things we can find on our coins sure comical. You should see some that I have been finding. My most comical ones are two identical Cal. state quarters that have some big die gouges on the reverse side that makes it look exactly like John Muir has thrown a club at the condor bird and even there are some smaller die gouges that looks like the feathers are falling out of the condor. then I have quite a few of the Cal quarters that looks like John Muir has a dagger in his hand. Then I have a matching pair of MN. quarters that looks like a fireworks grand finale on the reverse from being struck thru something and it made hundreds of small dots deep into the coins . I have misplaced these MN ones somewhere here and having a problem rescueing them. would you like to see a photo of these if I can find them back ?
Taz tomorrow evening I will post you some photos of some of my funny coins if I can relocate them tomorrow. I gurantee everyone will get a kick out of seeing what can come from the mint these days.
Taz I hunted a long time this evening and could not find my two awesome Minnesota coins but I did find the California ones I told you about. you should see one of these in hand. I only found two of them from a entire box of the CA. quarters. the mint workers must have destroyed the most of them. notice how much the curved die gouge looks like Jokn Muir has hit the condor bird with it then look below the condors wings how much this like feathers falling out of the condor.also John Muir has a die gouge coming from his right hand and going down his leg and making it look like he has another club in his hand. the light blurred this out in my photo.