Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of rare earth oxide producer Molycorp (NYSE: MCP) surged 10% in intraday trading Wednesday on a report from the Energy Department saying that the U.S. is at risk of rare earth supply disruptions. 

So what: With China controlling about 95% of the world's rare earth reserves, the report highlights the importance for the U.S. to diversify its sources and cut its dependence on Chinese supplies. It should come as no surprise then, that Molycorp -- the only rare earths producer in the Western Hemisphere -- as well as Rare Element Resources (AMEX: REE) are up big on the news.

Now what: For most Fools, Molycorp is still too risky to take a chance on. While it might be tempting to ride the rare earth momentum, Molycorp's nearly 200% gain over the past six months and current $3 billion market cap are pretty difficult to justify. Of course, with the looming modernization of its Mountain Pass mine, Molycorp seems like a sexy speculative opportunity for less risk-averse investors.

Interested in more info on Molycorp? Add it to your watchlist.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Fool's disclosure policy always gets a perfect score.