In 1885, the discovery of neodymium was announced by splitting a relatively common earth called didymium into two new earths. The two new elements praseodymia (green didymia) and neodymia (new didymia), which are now known as praseodymium and neodymium, respectively.

Neodymium, a member of the lanthanide series of elements, is a silvery-white rare-earth metal. Commercial-grade neodymium is obtained from monazite sand, which is a mixture of phosphates of calcium, thorium, cerium, and is often 50% rare-earth by weight. Nearly 25% of naturally occurring neodymium is made up of radioactive 144Nd. Its incredibly long half-life of 2,100,000,000,000,000 years has preserved its existence since the creation of the earth.

Neodymium is reactive to air and moisture. It tarnishes to form a light-blue oxide (Nd3O3), that flakes away to expose more metal for further oxidation. It has too little strength for structural use but has some value as an alloying agent and as a catalyst. Neodymium is used in the fabrication of artificial ruby for laser applications. In a pure form, it is useful in the glass industry as it produces the only bright-purple glass known. In a cruder state, it is used to eliminate the greenish tint in glass that has a high iron content. Neodymium is also used to make special glass that transmits the tanning rays of the sun but not the unwanted heat rays.

BCIT Chemistry Resource Center
http://nobel.scas.bcit.ca/resource/