Minerals which comprise of one or more rare earth elements as major metal components are called rare earth minerals. Rare earth minerals are usually found in association with alkaline to peralkaline igneous complexes, in pegmatites associated with alkaline magmas and in or associated with carbonatite intrusives. Perovskite mineral phases are common hosts to rare earth elements within the alkaline complexes. Mantle derived carbonate melts also are carriers of the rare earths. Hydrothermal deposits associated with alkaline magmatism contain a variety of rare earth minerals. The shortage of these minerals is what drove the name “rare earth”. The first rare mineral exposed was a compound of cerium named gadolinite, yttrium, iron, silicon and additional minerals. In 1787 at a quarry in the village of Ytterby, Sweden, rare earth elements became recognised to the entire world with the detection of”ytterbite” – a black mineral- and the pioneer behind such a discovery was Lieutenant Carl Axel Arrhenius. It literally took an additional 30 years for investigators to understand and learn that further elements were enclosed in the two ores ceria and yttria. The first rare mineral exposed was a compound of cerium named gadolinite -yttrium, iron, silicon and additional minerals. Rare earth elements or rare earth metals comprise a set of 17 chemical elements in the periodic table. Despite the assumption one can make due to the name, there are vast amounts of rare earth minerals found in crust of the earth. At 68 parts per million, cerium is the 25th most plentiful element. Rare earth elements are classically spread and not often found concentrated as rare earth minerals in economically useable ore deposit due to their geochemical properties. The 1940’s was when the chemical ion exchange procedures were created, with the aim to separate and purify the rare earth elements. Source