Doug Casey: The REEs are a group of 17 elements that you may recall from your high school chemistry class. They take up two rows in the periodic table, sitting by themselves at the bottom of the chart. They're chemically similar to each other.

REEs are widely dispersed on the Earth's surface. They aren't "rare" per se, but since they're not generally concentrated, you only rarely find deposits that are rich enough to qualify as a mine for elements like germanium, gadolinium, ytterbium, yttrium, or 14 others with exotic and obscure names. They're basically all minor byproducts of mines for other elements—largely aluminum or zinc. They've only recently found significant uses with the development of high-tech, especially electronics and magnets. Fifty years ago, they were basically just chemical curiosities.

The US has one pure REE mine, the Mountain Pass, in the California desert near Nevada. In fact, it's the only one in the Western hemisphere. Now owned by MP Materials (MP: NYSE $25), I have no opinion on the operation. It went bankrupt under its last owner—perhaps it will do better this time around.

International Man: Former Chinese leader Deng Xiaoping once said, "The Middle East has oil. China has rare Earth."

Today, China dominates the production and processing of REEs.

Why is that?

How likely is it that the US or someone else will be able to break China's stranglehold soon?