Rocks are a food source of Stegarbasaur and Cementasaur usually, but are edible for most other species in some way.
Granite: a heavy, strong material that is usually a first choice amongst rock eating species
Quartz: lighter, less common rock for rock eating secies
Shale: a smooth, easily breakable rock that rock eating species adore. simmilar to Dough
Mud Stone: a more, liquidy rock such as that to us as soggy bread. usually not the first choice of a rock eating speciesA
Ore: extremly easily digestible fiber like substance for Rock eating species