small stone

[BeachComber7]

Found this when I was at a river, it is maybe sandstone. It's interesting.

 

[GatorBoy]

First... that looks like midden patina on it. Can you show the other side? My guess would be that it was used as an abbrading stone.

 

[BeachComber7]

I edited the post and added pic of the back of the stone. Its small, almost 3 inches long and an inch and a half wide.

 

[GatorBoy]

It looks like an abbrading stone. Like a sanding block. The indent is probably where the thumb went while holding it.

 

[BeachComber7]

Patina? Thought it was the original outside of the stone that was worn away! I've seen oyster shells with that stuff on it.
You are right, I just put my thumb in it and it fits perfectly. Learn something new every day! Been looking at this stone now for a week or more, finally decided to post it for opinions. Thanks Bill.

 

[GatorBoy]

No problem. The patina is the staining that in this case happens from being burried for a long time in dark compost like soil. That is found in a midden with decayed plant and animal matter. Those oyster shells you are reffering to were part of the shell midden. In an area like that where a midden has eroded into water with other shells and things you can look for that patina on things to tell you it is an artifact. Even white shell will often at least have a pinkish look as compaired to the rest.