Oooh! That was funny! (sorry) but your piece of rock was busted by something, but not a hand. Funny too- I nearly took home a pice of rock that looked just like that- same type of rock and break even. I picked it up and looked and looked-- and looked some more. But no. Even seemingly insignificant little scrapers were made with some care and attention. If you have to look several times and still are not sure, it probably isn't man-made. At least that's my experience. Keep on keepin' on, man! Yakker