It looks like a nice thumbnail scraper, or maybe even an old flintlock flint? It is hard to tell from the photo, but the one edge looks like it might have created a few sparks in it's day?
I think Redbeard may be on to something. NA and whites did make flint striker for their guns when the good stuff could not be found. If it is a scraper that was used much you will see use sign on the scraping end. Good eye