Welcome to TreasureNet. Please post different photos of your item with a scale (ruler) to show size. Tell us what it is made of, etc...and someone will chime in. Happy Hunting, Sub
I'm with OD. Maybe a piece of old ceramic pottery or jug?. Looks like it got tumbled around in a river of rocks, sand and silt, for a few decades. I'm pretty sure it's not an ancient stone tool of any kind.