Most of us would be hard-pressed to locate Inner Mongolia, Jiangxi, or Guangdong on a map. Yet many of the high-tech devices we depend on—cell phones, laptops, and hundreds of others—would not exist without an obscure group of elements mined, sometimes illegally, in those three and other regions of China.
Rare earths, as the elements are called, were discovered beginning in the late 18th century as oxidized minerals—hence "earths." They're actually metals, and they aren't really rare; they're just scattered. A handful of dirt from your backyard would probably contain a smidgen, maybe a few parts per million. The rarest rare earth is nearly 200 times more abundant than gold. But deposits large and concentrated enough to be worth mining are indeed rare.
The list of things that contain rare earths is almost endless. Magnets made with them are much more powerful than conventional magnets and weigh less; that's one reason so many electronic devices have gotten so small. Rare earths are also essential to a host of green machines, including hybrid cars and wind turbines. The battery in a single Toyota Prius contains more than 20 pounds of the rare earth element lanthanum; the magnet in a large wind turbine may contain 500 pounds or more of neodymium. The U.S. military needs rare earths for night-vision goggles, cruise missiles, and other weapons.