what's that in my rice

I was starting some rice.  I thought I saw something in the water as I stirred, when it was about to boil.  So I got it out. 

At first I thought it was a rock.  It was gray and rounded and irregular.  But I smashed it between my fingers pretty easily. It came apart like sandstone but wasn't made of sand.  I washed it off my fingers.

"Should we still eat the rice?" I asked Ming.  I stirred more looking for more things, but I didn't see any.

He said, "It wasn't alive, and it wasn't dead." 

I said, "It wasn't poop."  And it wasn't an egg. 

So he said the rice was okay to eat.  I'm kind of grossed out, though.  Should I eat the rice?

I said we should go to whatsthatinmyrice.com.