1st - I noticed this was your very first post - so, Welcome Aboard Nittany! Take a look at Forum: New York for information (i.e., clubs, etc.) directly related to your state.
2nd - I moved ya from TODAY'S FINDS! over to WHAT IS IT? for more exposure.
I took it to a museum in my town to see if if an archivist recognized it with no luck. This area has a rich presence of Native Americans. I was curious if possibly it could be an artifact. This area was also under a shallow sea and it has tons of fossils. I’ve never seen an fossil from the area look like that
I've seen all kinds of natural rock formations including some that looked like fried eggs. Perhaps there's some
kind of natural process that could have created this but there should be some more of them thereabouts. The back
looks exactly like a metal button with the loop torn from the back. Have you scanned it with your detector or
pinpointer? If definitely non metallic I'd have to go with HuntinDog!
I think it is part of a button. There would probably have been a metal back and the stone would have been held to it by a rim that would have crimped over the lip you pointed out to us.