Indian artifact collectors...what is this?

[dirtsearcher]

I found this along the shore of the lake where I live when the water level was down.It looks like it may have been an axe head or something similar.It fits in your hand as you can see in the pics.The part of your hand between your thumb and first finger fits in the groove and then there is a ridge on the back for your finger to hold it securely.But with the grooves in it,it looks like string was wrapped around it.

 

[FunWithTreasure]

Looks like a piece of leverite. LOL Thought maybe it was a sharpening stone but the lines are to wavy. Which makes me think its a geofact. But hold onto it just incase im wrong.

 

[DANGLANGLEY]

I'm guessing also but it looks like a rather odd naturally formed rock. I would also keep it because it's very interesting. Have a great day!

DANGLANGLEY