n. A bright, silvery rare-earth metal element, found in monazite and bastnaesite and used for coloring glass and for doping some glass lasers. Atomic number 60; atomic weight 144.24; melting point 1,024°C; boiling point 3,027°C; specific gravity 6.80 or 7.004 (depending on allotropic form); valence 3. See Table at element.