Neodymium belongs to the lanthanide series and atomic number 60, is one of the most reactive rare earth metals It's a hard, slightly malleable silvery metal that quickly tarnishes in air and moisture. Neodymium compounds were first commercially used as glass dyes in 1927, and they remain a popular additive in glasses. Another important use of neodymium is as a component in the alloys used to make high-strength neodymium magnets—powerful permanent magnets. Adding neodymium to magnesium or aluminum alloy can improve the high temperature performance, air tightness and corrosion resistance of the alloy, and is widely used as an aerospace material.