A brittle, crystalline, highly diamagnetic metallic element with a very low thermal conductivity and a pinkish-white luster, used in alloys to form sharp castings for objects sensitive to high temperatures and in various low-melting alloys for fire-safety devices. Atomic number 83; atomic weight 208.98; melting point 271.3°C; boiling point 1,564°C; specific gravity 9.78; valence 3, 5. See Periodic Table.