Neodymium ( /ˌniːɵˈdɪmiəm/ nee-o-dim-ee-əm) is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Although neodymium is classed as a "rare earth", it is no rarer than cobalt, nickel, and copper ore, and is widely distributed in the Earth's crust. Most of the world's neodymium is mined in China.
Neodymium compounds were first commercially used as glass dyes in 1927, and they remain a popular additive in glasses. The color of neodymium compounds—due to the Nd(III) ion—is often a reddish-purple but it changes with the type of lighting, due to fluorescent effects. Some neodymium-doped glasses are also used in lasers that emit infrared light with wavelengths between 1047 and 1062 nanometers. These have been used in extremely high power applications, such as experiments in inertial confinement fusion.
Neodymium is also used with various other substrate crystals, such as yttrium aluminum garnet in the Nd:YAG laser. This laser usually emits infrared waves at a wavelength of about 1064 nanometers. The Nd:YAG laser is one of the most commonly used solid-state lasers.
Another chief use of neodymium is as the free pure element. It is used as a component in the alloys used to make high-strength neodymium magnets – the most powerful permanent magnets known. These magnets are widely used in such products as microphones, professional loudspeakers, in-ear headphones, and computer hard disks, where low magnet mass or volume, or strong magnetic fields are required. Larger neodymium magnets are used in high power versus weight electric motors (for example in hybrid cars) and generators (for example aircraft and wind turbine electric generators).