Neodymium is a rare-earth element. It is a hard, slightly malleable silvery metal that quickly tarnishes in air and moisture. When oxidized, Neodymium reacts quickly to produce pink, purple/blue and yellow compounds. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach, and is not found naturally in metallic form or unmixed with other lanthanides, It is present in significant quantities in the ore minerals monazite and bastnäsite. Although it belongs to the rare-earth metals, Neodymium is not rare at all. The reserves of Neodymium are estimated at about eight million tonnes, which is the second highest among rare-earth elements, following cerium.
Neodymium metal dust is combustible and therefore an explosion hazard. Neodymium dust and salts are very irritating to the eyes and mucous membranes, and moderately irritating to skin. Breathing the dust can cause lung embolisms, and accumulated exposure damages the liver. Neodymium also acts as an anticoagulant, especially when given intravenously.
Art and Design
The first commercial use of purified Neodymium was in glass coloration, starting with experiments by Leo Moser in November 1927. He worked with scientists from Germany and England in the 1920s to perfect his process. Glass manufacturers from Czechoslovakia, Italy, Spain, England, and the U.S. followed example, adding the compound to art glass, tableware, jewellery, and other items to take advantage of its colour-changing properties.
The resulting “Alexandrite” glass remains a signature colour of the Moser glassworks to this day. The colour of Neodymium compounds is often a reddish-purple, but it changes with the type of lighting, because of the interaction of the sharp light absorption bands of Neodymium with ambient light enriched with the sharp visible emission bands of Mercury, Trivalent europium or Terbium.
Sunlight is made up of relatively equal parts of blue and violet light, whereas fluorescent light has more blue than violet. Neodymium glass is great at filtering out the reds and yellows and only letting the other colours come through. This means more violet ends up coming through in sunlight, giving the neodymium glass a purple appearance, and more blue shows through in fluorescent light, making the glass appear blue.
Due to the presence of Neodymium oxide (Nd²O³) in the glass, Neodymium glass changes colour according to different lighting conditions. The glass appears lilac (or sometimes pink) in natural sunlight or yellow artificial light, and smokey blue in fluorescent/white light. Glassware containing Neodymium was produced in several countries, including Scandinavia, Italy, and the Czech Republic. The shades of lilac, pink and blue can vary greatly depending on the glass mixture.
Costume jewellers such as Weiss Company, Kramer of New York, and others in the U.S. and Europe took advantage of the twin nature of Neodymium glass, creating neodymium glass rhinestones that they used in their pieces.
Neodymium glass and Neodymium beach glass is quite scarce since many of the early commercial makers of Neodymium glass are now closed, and most made their Neodymium pieces for a limited time. Those who still use Neodymium Oxide to dye glass rarely make mass-produced products, but instead make one-off bowls, vases, and decorative pieces. Glass artist Dale Chihuly has used Neodymium in several of his glass sculptures, chandeliers, and more. Other current Neodymium glassmakers are in the Czech Republic, the U.S., and China.
The most important use for Neodymium is in an alloy with Iron and Boron to make very strong permanent magnets. Developed independently in 1984 by General Motors and Sumitomo Special Metals, Neodymium magnets are the strongest type of permanent magnet available commercially.
This discovery made it possible to make electronic devices much smaller, including mobile phones, microphones, loudspeakers and electronic musical instruments.
Neodymium magnets are perfectly safe for humans and animals although some precaution is needed when handling them. Some Neodymium magnets are strong enough to cause some serious damage to fingers and/or hands if they get jammed between a strong magnet and metal or another magnet.
Neodymium magnets have been tested for medical uses such as magnetic braces and bone repair, but biocompatibility issues have prevented widespread application.
These magnets are widely used in such products as microphones, professional loudspeakers, in-ear headphones, high performance hobby DC electric motors, 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 such as hybrid cars and generators in aircrafts and wind turbine electric generators.
Neodymium in glass also has industrial and scientific uses. The same process that filters the light in decorative glass is useful in lasers, welding and glassblowing goggles, astronomical filters, car rear view mirrors, and more.
Neodymium and Didymium glass are used in colour-enhancing filters in indoor photography, particularly in filtering out the yellow hues from incandescent lighting. Similarly, neodymium glass is becoming widely used more directly in incandescent light bulbs. These lamps contain neodymium in the glass to filter out yellow light, resulting in a whiter light which is more like sunlight. Similar to its use in glasses, Neodymium salts are used as a colorant for enamels.