A silvery-white, malleable, ductile, metallic element of the lanthanide series, with unusual magnetic properties including a Curie point at room temperature, obtained from the minerals monazite and bastnaesite and used in improving high-temperature characteristics of iron, chromium, and related alloys, and as a contrast medium for magnetic resonance imaging. Atomic number 64; atomic weight 157.25; melting point 1,313°C; boiling point approximately 3,273°C; specific gravity from 7.901; valence 3. See Periodic Table.