Considering that there's a side quest in to where a rock connoisseur is looking for a rare type of flint, I'd say theres definitely different flavors of rock. And in terms of cooking, the gorons have grills where they literally just cook rocks. I'm not sure if they're trying to metamorphize them into different rocks or what's actually going on, but they don't eat their rocks raw. I wonder if concrete would be like a soup for them?