It's kind of strange how it's dished out at the toplike some sort of hand formed pottery. But Mother Nature never ceases to amaze either. I also once found a perfectly egg shaped rock (hard as a rock) that smelled pretty bad. I kept it for a while but it got lost in a move or I disposed of it due to the smell either one. It had a small chip in it, but other than that it was a perfect little stinky egg looking rock. About half the size of a chicken egg.