The battle over the world's rare earths

China’s trade policies have again been under the spotlight in the past few months. Of course, the renminbi exchange rate has never left the agenda. But recently, another more esoteric, albeit equally important, issue for the preservation of our gadget-ridden, high-tech world has risen to prominence and captured the global headlines.

In July, China said it would cut export quotas of “rare earths” by around 40% from 2009 levels, citing a need to protect its reserves. Exports in the second half of 2010 will be 72% lower than in the second half of 2009.

Rare earths have magnetic and luminescent properties and are used in a myriad technologies. These range from military uses...