rare earth, rare earth metal, rare earth alloy, rare earth oxide, rare earth boride, rare earth fluoride, rare earth chloride, rare earth carbonate, rare earth nitrate, rare earth acetate, Lanthanum, Cerium, Praseodymium, Neodymium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Scandium, Yttrium