Shen Zhou Mining (AMEX:SHZ), Rare Element (AMEX:REE), Qiao Xing, (Nasdaq:XING), Molycorp (NYSE:MCP), General Moly (AMEX:GMO), Avalon (AMEX:AVL) in the

After the explosion in stock prices of companies with large exposure to rare earths like China Shen Zhou Mining & Resources, Inc. (AMEX:SHZ), Rare Element (AMEX:REE), Qiao Xing Universal Resources, (Nasdaq:XING), Molycorp, Inc (NYSE:MCP), General Moly (AMEX:GMO) and Avalon Rare Metals (AMEX:AVL), they predictably have fallen back to earth in price, as the media focus has already shifted elsewhere.

Rare earths, while being extremely important, are far more difficult to mine economically than most other raw materials, as they are hard to find in concentrations, and the separation process also adds to them being difficult to mine profitably.

This isn't to say demand isn't there, as it is, but China at this time accounts for about 95 percent of the market, and while other companies are ramping up exploration and production on the news China has cut back on their export quotas by about 95 percent, it'll take a couple of years before the production side becomes meaningful, although some companies will be able to enlarge operations at existing projects.

With the high share price after the run-up, it's probably best to wait until they pull back to engage at a better entry point than to invest now, although it depend on the company one is interested in, as some have already dropped dramatically.

General Moly is trading at $6.36, down $0.15, or 2.30 percent, as of 11:48 AM EST. Molycorp was trading at $50.97, down $1.43, or 2.73 percent. Qiao Xing Universal Resources was at $2.83, down $0.07, or 2.41 percent. Rare Element was trading at $14.67, down $0.41, or 2.72 percent. China Shen Zhou Mining & Resources, Inc. was at $9.08, gaining $0.29, or 3.30 percent. Avalon Rare Metals was trading at $6.34, down $0.16, or 2.46 percent.