“Rare earths” is a collective name given, for historical and practical reasons, to a set of metal elements in the periodic table. Rare earth elements (REEs) are elements called “trace elements” in most natural environments. The first use of REEs was attested in 1885, when cerium was used in gas sleeves in the city of Vienna. Europe consumes 10% of the REEs produced in the world. REE deposits can be divided into two major categories: primary or endogenous deposits associated with magmatic and hydrothermal processes and secondary exogenous deposits linked to sedimentation and/or climatic processes. Greenland benefits, in particular, from varied geological settings favorable to the presence of REE deposits attractive to exploration companies. The main REE occurrences in Greenland are situated in carbonatites, alkaline intrusions, pegmatites and paleoplacers.