atomic number 58, Ce, cerium - a ductile gray metallic element of the lanthanide series; used in lighter flints; the most abundant of the rare-earth group

atomic number 60, Nd, neodymium - a yellow trivalent metallic element of the rare earth group; occurs in monazite and bastnasite in association with cerium and lanthanum and praseodymium

atomic number 59, Pr, praseodymium - a soft yellowish-white trivalent metallic element of the rare earth group; can be recovered from bastnasite or monazite by an ion-exchange process

atomic number 62, samarium, Sm - a gray lustrous metallic element of the rare earth group; is used in special alloys; occurs in monazite and bastnasite

mineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition