I'm a bit flabbergasted by DD's delight in chewing on rocks that she can find. She's 13 months with just a few teeth, and seems to delight in gnawing on our fireplace hearth, which is made out of real stone. The other day when we were out on the porch playing she had a good chew on a rock we had out there. ?? Is she missing something in her diet? Is it just a weird phase? I'd appreciate your collective thoughts on the matter, as DH and I are feeling slightly concerned about it.