It looks to me like a tooth of a mammal, probably an ungulate (hoofed mammal), although what kind I can't say, although it looks large. Can you send more pictures, taken from different angles? Where did you find it?

I think it probably is biological - the pattern of erosion on the left suggests calcium carbonate dissolution while the pattern on the right suggests laminae. If it is small, it could be a pelecypod shell; if large, a tooth.

The area this person cites is generally noted for producing marine fossils, so it indeed might be an eroded oyster shell. I sent the earlier picture to a different scientist, who suggested it might be a highly erode mastodon tooth, but if so it is rather small, but it 'could be". It would be useful to know precisely where these came from near Pine Mountain - and also to see the actual specimen.