slate is a kind of metamorphic rock
metamorphic_rock is rock. metamorphic_rock is not stone. slate is not another_type_of_hard_rock. slate is not sedimentary_rock. slate is metamorphic_rock. slate is another_type_of_hard_rock. slate is sedimentary_rock. metamorphic_rock is not rock. metamorphic_rock is stone. slate is not metamorphic_rock.