From Foreign Policy:

Today, however, rare-earth mining is almost nonexistent outside China, which came to dominate the market in the 1980s and ’90s by cutting world prices and now controls as much as 97 percent of the supply of some of the elements. The United States’ only major rare-earth mine, a complex in Mountain Pass, California, that was once the world’s leading producer of the minerals, shut down in 2002.

But the limited supply of the minerals in the marketplace is the result of economics and environmental concerns, not scarcity. Even with iPads flying off the shelves and high-end electric cars on showroom floors, the world consumes only a tiny amount of rare earth — about 130,000 metric tons of it a year, or just over a tenth of the amount of copper produced last February alone. Market forecasters expect the global trade in rare earths to reach $2 billion to $3 billion by 2014, but even that amounts to barely 1 percent of today’s iron market. And rare earth elements aren’t actually worth very much at the mine — most of their market value is added in the refining process.