Several years ago, for example, China suddenly slashed exports of rare earths.
It also contains coal, iron, uranium, gold, copper, rare earths, gemstones and much more, including, of course, fish.
Inner Mongolia's backward economy was booming thanks to demand for its minerals, ranging from copper to rare earths, but especially its coal.
But the driving force behind a lot of scientific activity is far more romantic than many non-scientists appreciate and the search for other Earths, with their tantalising promise of other life forms, is about as romantic as it gets.Keep numbers, then, in their proper place for counting things.
In "heavy" rare earths such as dysprosium, which helps magnets keep their properties at high temperatures, its market share is nearly 100%.China cites environmental concerns to justify its export curbs.
"The Chinese realised the strategic importance of rare earths decades before the West," says Alistair Stephens of Arafura Resources, in Perth, Australia.
To safeguard its dwindling surpluses, the Chinese government has been stockpiling rare earths, taxing them and imposing ever-smaller export quotas.
The speculative frenzy is being driven by investors outside Japan and China, the countries that consume most of the world's rare earths, according to John Kaiser, whose website, Kaiser Bottom Fish, tracks rare-earth firms.
For the Chinese, rare earths are simply not rare enough.
For though life can certainly evolve in oceans, as it did on Earth, it probably needs the chemical and climate-regulating contributions of continents to do so.Unfortunately, many exoplanetologists think super-Earths will be covered entirely by oceans, since their high gravity will make it hard for areas of light rocks (such as those which form continents on Earth) to rise above sea level.
Its unannounced but effective suspension, at the height of an earlier Diaoyu/Senkaku crisis in 2010, of rare-earths exports to Japan prompted a new examination of the financial prospects of other rare-earth mines.
