Not sure what to think of this.

[Islandhunter]

Found this today walking a saltwater shoreline. Not sure if it is natural or an artifact. I couldn't leave it behind. It appears to have some big flakes taken off one side and the other side is smooth for the most part. Any thoughts?

 

[old digger]

Natural rock eroded by nature.

 

[unclemac]

i walk a shoreline where I can pick those up with every step.

 

[monsterrack]

It's natural stone, was broken by many different actions.

 

[rock]

Yes natural shows no cortex altered.