in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium. Scandium and yttrium are considered rare earth elements since they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties.
Despite their name, rare earth elements (with the exception of the radioactive promethium) are relatively plentiful in the Earth's crust, with cerium being the 25th most abundant element at 68 parts per million (similar to copper). However, because of their geochemical properties, rare earth elements are typically dispersed and not often found in concentrated and economically exploitable forms. The few economically exploitable deposits are known as rare earth minerals. It was the very scarcity of these minerals (previously called "earths") that led to the term "rare earth". The first such mineral discovered was gadolinite, a compound of cerium, yttrium, iron, silicon and other elements. This mineral was extracted from a mine in the village of Ytterby in Sweden (Earth)
Virtually every technologial product of modern Union society needs Rare Earth minerals. Thus mining and trade of these materials are very important and highly profitable.
Little Plastic Sacks filled with a set weight (or pressed into coins and coated with plastic) of Terbium or Samarium are a readily accepted form of payment everywhere in the known Universe.
|21||Sc||Scandium||from Latin Scandia (Scandinavia), where the first rare earth ore was discovered.||Light aluminium-scandium alloy for aerospace components, additive in Mercury-vapor lamps.|
|39||Y||Yttrium||for the village of Ytterby, Sweden, where the first rare earth ore was discovered.||Yttrium-aluminum garnet (YAG) laser, yttrium vanadate (YVO4) as host for europium in TV red phosphor YBCO high-temperature superconductors, yttrium iron garnet (YIG) microwave filters.|
|57||La||Lanthanum||from the Greek "lanthanein", meaning to be hidden.||High refractive index glass, flint, hydrogen storage, battery-electrodes, camera lenses, fluid catalytic cracking catalyst for oil refineries|
|58||Ce||Cerium||for the dwarf planet Ceres.||Chemical oxidizing agent, polishing powder, yellow colors in glass and ceramics, catalyst for self-cleaning ovens, fluid catalytic cracking catalyst for oil refineries, ferrocerium flints for lighters|
|59||Pr||Praseodymium||from the Greek "prasios", meaning leek-green, and "didymos", meaning twin.||Rare-earth magnets, lasers, core material for carbon arc lighting, colorant in glasses and enamels, additive in didymium glass used in welding goggles, ferrocerium firesteel (flint) products.|
|60||Nd||Neodymium||from the Greek "neos", meaning new, and "didymos", meaning twin.||Rare-earth magnets, lasers, violet colors in glass and ceramics, ceramic capacitors|
|61||Pm||Promethium||for the Titan Prometheus, who brought fire to mortals.||Nuclear batteries|
|62||Sm||Samarium||for Vasili Samarsky-Bykhovets, who discovered the rare earth ore samarskite.||Rare-earth magnets, lasers, neutron capture, masers|
|63||Eu||Europium||for the continent of Europe.||Red and blue phosphors, lasers, mercury-vapor lamps, NMR relaxation agent|
|64||Gd||Gadolinium||for Johan Gadolin (1760–1852), to honor his investigation of rare earths.||Rare-earth magnets, high refractive index glass or garnets, lasers, X-ray tubes, computer memories, neutron capture, MRI contrast agent, NMR relaxation agent|
|65||Tb||Terbium||for the village of Ytterby, Sweden.||Green phosphors, lasers, fluorescent lamps|
|66||Dy||Dysprosium||from the Greek "dysprositos", meaning hard to get.||Rare-earth magnets, lasers|
|67||Ho||Holmium||for Stockholm (in Latin, "Holmia"), native city of one of its discoverers.||Lasers|
|68||Er||Erbium||for the village of Ytterby, Sweden.||Lasers, vanadium steel|
|69||Tm||Thulium||for the mythological northern land of Thule.||Portable X-ray machines|
|70||Yb||Ytterbium||for the village of Ytterby, Sweden.||Infrared lasers, chemical reducing agent|
|71||Lu||Lutetium||for Lutetia, the city which later became Paris.||PET Scan detectors, high refractive index glass|