Rare Earth Element
As defined by IUPAC, rare earth elements ("REEs") or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium. Scandium and yttrium are considered rare earth elements since they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties.
Despite their name, rare earth elements (with the exception of the radioactive promethium) are relatively plentiful in the Earth's crust, with cerium being the 25th most abundant element at 68 parts per million (similar to copper). However, because of their geochemical properties, rare earth elements are typically dispersed and not often found concentrated as rare earth minerals in economically exploitable ore deposits. It 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 compound of cerium, yttrium, iron, silicon and other elements. This mineral was extracted from a mine in the village of Ytterby in Sweden; several of the rare earth elements bear names derived from this location.
Read more about Rare Earth Element: List, Abbreviations, Discovery and Early History, Origin, Geological Distribution, Global Rare Earth Production
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“It is so rare to meet with a man outdoors who cherishes a worthy thought in his mind, which is independent of the labor of his hands. Behind every man’s busy-ness there should be a level of undisturbed serenity and industry, as within the reef encircling a coral isle there is always an expanse of still water, where the depositions are going on which will finally raise it above the surface.”
—Henry David Thoreau (1817–1862)
“The earth has become small, and on it hops the last man, who makes everything small. His race can no more be exterminated than the flea can be. The last man lives the longest.”
—Friedrich Nietzsche (1844–1900)
“Other sins only speak; murder shrieks out:
The element of water moistens the earth,
But blood flies upwards, and bedews the heavens.”
—John Webster (1580–1625)