Looking at it, I guess it looks more like bones to me. I think the cracks should vary more - some being thick and having more depth and some being thinner. I don't have an artis's eye or experience, so it's hard for me to explain.
I commented on your other stonework peice, too. I think maybe it could use thicker lines. It needs to look more heavy, in my opinion. Again, I like your work, this is meant to be constructive criticism. :)