Used in the making of certain light bulbs. In 1841, Mosander extracted cerite which became didymium. In 1885 he separated didymium into two different elements giving us Neodymium. Neodymium is present in the minerals monazite, and bastasite, which are principal sources of rare-earth elements. The metal has a bright silvery metallic luster and one of the more reactive rare-earth metals.
Neodymium quickly tarnishes in air, forming an oxide that spills off and exposes metal to oxidation.
The glass has been used in astronomical work to produce sharp band by which spectral lines may be calibrated.