Ytterbium is not found free in the earths crust but in ores most commonly Monazite. Ytterbium is used in portable x-ray machines due to its radioactive properties and also used in earthquake monitoring stations. Ytterbium reacts quickly with air and water and tarnishes readily. Ytterbium was discovered in Ytterby the Swedish village which Yttrium, Terbium and Erbium also draw their name from. It is a solid metal at room temperature with a melting point of 824°c and a boiling point of 1196°c.
Jean de Marignac