By Jim Cramer, TheStreet

The headlong rush into batteries for cars that plug into our coal-based electric system -- as opposed to vehicles powered by abundant and cleaner natural gas -- has taken a new twist with the recognition that we don't have enough of the rare earth metals that go into those batteries to produce them on the mass scale required.

You need a periodic table to really tell the score in this business, but, as Bloomberg said in an astute story this morning, more than 90% of the rare earth minerals we need are in China. And, as we know, China is not a fair trader.

Rare earth minerals are the worst combination: There aren't enough of them, and they're in China. No wonder lanthanum oxide, a key ingredient in batteries, has risen sevenfold in just a few months. That's a typical run.

Americans are desperate to play it, hence the run in Molycorp (MCP) to $2.6 billion in market cap with almost no revenue and huge losses. It doesn't matter. When you get into a frenzy, you can go to $5 billion in market cap before people figure out that perhaps they are paying too much.

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As an aside, this was the most talked-about stock wherever I went this weekend, and everyone seemed to have bought it at $11!

Of course, all of this is extraordinarily good news for U.S. coal companies like Massey (MEE), which I think gets a high bid, or Arch (ACI), Patriot (PCX) or Peabody (BTU). The coal-based utility system has been lacking an overnight driver to sales; it suddenly has one.

If we were logical about it, we would be trying to figure out how to hook up as a nation to our natural-gas stockpile. The $3.30 price is very competitive at this point, even against coal -- if you factor in the costs of building new, less-polluting plants.

But the prices of the big nat-gas players, like Range (RRC) and Chesapeake (CHK) and Ultra (UPL), reflect nothing but the decision to go battery/coal/scarce metals over abundant natural gas. It's why I like the coal stocks so much and why I know Molycorp isn't done yet. As crazy as that is.

At the time of publication, Cramer had no positions in the stocks mentioned.

Jim Cramer is co-founder and chairman of TheStreet. He contributes daily market commentary for TheStreet's sites and serves as an adviser to the company's CEO.

Click here to follow Cramer's trades for his Charitable Trust.

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