metamorphic rocks are formed by rocks being exposed to extreme heat and pressure
metamorphic_rock is rock. metamorphic_rock is not stone. marble is not useful_metamorphic_rock. slate is metamorphic_rock. marble is metamorphic_rock. marble is not metamorphic_rock. metamorphic_rock is not rock. metamorphic_rock is stone. marble is useful_metamorphic_rock. slate is not metamorphic_rock.