I would have picked it up also.
It has definitely been tumbled around in a stream or lake shore, so some of it identifying characteristics are gone.
Describe in words what you see.
Where did you find it?
Is it translucent? Probably not in the middle, but what about the edges?
Looks kind of glassy. How would you describe it's texture?
How hard is it?
I see a couple of little clear bubble like inclusions along the top right.
Hard to say what it is, based just on the pic. Give us some more to work with.
Rob