That’s a good point. I’ve never heard it specified (outside of art) how can killed Abel, but assuming they were farmers, it’s reasonable that it could have been with a rock: the only times I’ve consistently found decently-sized rocks was when I needed to dig a hole. Not when I wanted a rock, mind, but when I needed a hole.

Maybe it’s because of where I grew up, but I could usually find a serviceable stick more easily than a decent rock.