The Columbia Encyclopedia, Sixth Edition. Columbia Encyclopedia World Factbook Columbia Gazetteer American Heritage Coll.
Cerium is a soft, malleable, ductile, iron-grey metal with hexagonal or cubic crystalline structure.
It is slightly harder than lead. It is the most abundant of the rare-earth metals of group IIIb of the periodic table . It does not tarnish rapidly in dry air but quickly loses its luster in moist air. It oxidizes slowly in cold water and rapidly in hot water. It is attacked by solutions of alkalis and by concentrated or dilute acids.