Very smooth half sphere rock found in creek

[cloudboy]

Found this a few months ago in a dry creek bed. Western KY. It's very smooth to the touch. The bottom is flat and has a square indentation that is actually smoother than the area outside of the square. I have no idea what this is, but the nearly perfect shape and incredible smoothness of the rock seems unnatural?

 

[uniface]

Interesting !

 

[unclemac]

I have handled a different but similar object. Obviously intriguing but use unknown... you don't often get stumped like that

 

[unclemac]

perhaps natural....a crystal eroded out of the background matrix?

https://www.google.com/search?q=nat...6DSgQ_AUoAXoECAEQAw&biw=1536&bih=722&dpr=1.25

 

[alan m]

I think it is just a rock that got broken by the spade if a back hoe, still it is a cool find indeed.