It has been noted several times previously that the Rare Earths (RE), a sequence of elements with atomic numbers in the range from 58 (Ce) to 71 (Lu), are neither earths nor particularly rare. They are metals, whose ores are often found together with oxides of the "alkaline earths" (Ca, Mg), staples of the building industry, th while Cerium, for example, is the 25 most abundant element in the Earth's crust. However, the chemical similarity of all REs to each other and to Lanthanum, reflected in their alternative descriptor, Lanthanoids, made extraction of the separate elements difficult until...