region is a mean of igneous stone
igneous_rock is stone. groundmass is not igneous_rock. porphyry is igneous_rock. peat_soil_region is high_plasticity_soil_region. granite is igneous_rock. basalt is igneous_rock. igneous_rock is rock. igneous_rock is not stone. peat_soil_region is geographical_region. groundmass is igneous_rock.