what are rare earth elements
A rare earth element (REE) or rare earth metal (REM), as defined by IUPAC, is one of a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides, as well as scandium and yttrium.t 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 mineral composed of cerium, yttrium, iron, silicon and other elements.