What are rare earth elements?
Rare earth elements or rare earth metals are a collection of seventeen chemical elements in the periodic table, namely scandium, yttrium, and the fifteen lanthanides. Scandium and yttrium are considered rare earths since they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties.
The term "rare earth" arises from the rare earth minerals from which they were first isolated, which were uncommon oxide-type minerals (earths) found in Gadolinite extracted from one mine in the village of Ytterby, Sweden.
With the exception of the highly-unstable promethium, rare earth elements are found in relatively high concentrations in the earth's crust, with cerium being the 25th most abundant element in the earth's crust at 68 parts per million.
It is these important metals that make many of today's (and tomorrow's) green technologies possible, including hybrid car batteries, advanced medical systems, wind turbines, numerous household appliances, LEDs, and consumer electronics, thin film solar panels, and even oil refining.
