What are Rare Earths?
The Japanese call them “the seeds of technology.” The US Department of Energy calls them “technology metals.” They make possible the high tech world we live in today – everything from the miniaturization of electronics, to the enabling of green energy and medical technologies, to supporting a myriad of essential telecommunications and defense systems. They are the elements that have become irreplaceable to our world of technology owing to their unique magnetic, phosphorescent, and catalytic properties.
While named rare earths, they are in fact not that rare and are relatively abundant in the Earth's crust. What is unusual is to find them in quantities significant enough to support economic mineral development.
China became the world's dominant producer of rare earths in the 1990s. Because China sold rare earths at very low prices, mines like Molycorp’s Mountain Pass in California and others throughout the world were unable to compete. By 2000, China accounted for more than 95% of world rare earth production.
http://www.rareelementresources.com/rare-earth-elements