arrangemonk, igneous rock is not really crystalized like that, and sedimentary rock looks nothing like it - it is deposited in layers. Check out some more ref for getting believable rock forms, you will see repeating shapes of varying size.
Unfortunately I think the normal ends up coming across as rumpled up canvas, especially where that pinch is right next to the larger "rock" form, that really kills the impression that it's a rock. I'd recommend looking at more reference, and thinking about the natural processes that create the shapes and textures of rocks.