Rare Earth Metals/Minerals are used to refine petroleum products and are also used to manufacture electronic devices. Currently, China has a near monopoly on production and has reduced exports, driving up the price on many things - most notably gasoline. The US is working hard to reduce its dependence on China.
The following is a good primer for what you need to know about Rare Earth Metals...
1. Rare earth element: Defined. [Wikipedia]
2. China's Rare Metals exports curb is raising Gasoline Prices. [Blogging Stocks]
3. Beijing's Motives Behind Rare-Earth Metals. [Forbes]
4. How the H1-2011 Rare-Earth Export Quotas were allocated. [Resource Investor]
5. Are Rare Earth Elements actually rare? [Foreign Policy]
6. US on track to be Second Largest Rare Earths Producer. [Resource Investor]
7. 2011 spells desperate search for rare earth minerals. [International Business Times]
8. Rare earth metal recycling. [Green Living Tips]