It always helps if you give us some kind of content about it, not just a couple pictures.
Where was it when you found it, are the 2 sides concave? It could be a grinding stone for a metate, it could be broken chunkey stone, it could be just a stone. The pictures make it appear to be a broken chunkey stone, but that is based only on the pictures.
Looks natural to me
"Chunkey Stone"
Chunky was a native game that was widespread and popular. The game stones used are called chunkey stones and are also a class of artifacts known as a discoidal....
https://peachstatearchaeologicalsociety.org/index.php/22-game-stones/151-chunky-stones
https://archive.archaeology.org/0909/abstracts/pastime.html