Geologists have figured out that gas bubbles in magma (composed mostly of CO2 and H2O) create the holes in scoria. Scoria is also called cinder. It is used in gas-fired barbeque grills in place of charcoal briquettes. It is also used as aggregate in road construction and as a decorative, architectural aggregate. Crystals normally do not contain large holes, but some of the crystals of clinopyroxene and plagioclase and, less commonly, hornblende and olivine at Easy Chair Crater contain holes.