“Rare earths” are 17 chemical elements with awkward names and unusual properties. Their atomic numbers are 57–71, 21, and 39. Their two subfamilies, one scarcer and hence more valuable than the other, have similar chemistries, so they’re generally found and mined together.
Despite their name, rare earths are not geologically rare but are widely dispersed throughout the Earth’s crust. They are mined in few places and by few firms, though, because they tend not to occur in highly concentrated form. Further raising miners’ costs and risks, the world market for rare earths is modest (several billion dollars a year), volatile, complex, and dominated by China, where not all mines and exports are legal and transparent. One expert concluded that about half of 2015 global production was off the books. Continue reading “Clean energy and rare earths: Why not to worry”