Thulium

Element category: Lanthanide

Thulium is a bright, lustrous, soft, malleable, silvery rare earth metal, a member of the periodic table's lanthanide group. It is the second least abundant of the lanthanides only after promethium.

Thulium metal is rare and expensive, so it almost has no commercial applications. Holmium-chromium-thulium triple-doped Yttrium aluminum garnet (Ho:Cr:Tm: YAG, or Ho, Cr, Tm: YAG) is an active laser medium material with high efficiency. Thulium isotopes can be used as an X-ray source.