Tooth rocks appear in the Phazon Core of the Impact Crater. As their name implies, they are rocks resembling teeth. The rocks are embedded into the walls for Samus Aran to jump on. It would seem that they match the bone-like pillar in the middle of the room. They are named in concept art of the game. Several smaller rocks also resembling human canine teeth are also seen attached to walls and platforms. As of yet, it is unknown if they are made of calcium, or some other element/compound.