A relatively soft, malleable, stable rare-earth element occurring in gadolinite, monazite, and other rare-earth minerals. Atomic number 67; atomic weight 164.930; melting point 1,461°C; boiling point 2,600°C; specific gravity 8.803; valence 3. See Table at element.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.