Rare Earth Elements: What They Are, Where They Come From, and Why the World Is Fighting Over Them

Rare Earth Elements: What They Are, Where They Come From, and Why the World Is Fighting Over Them

The phrase "rare earth elements" is one of the more misleading terms in materials science. These 17 metallic elements are not particularly scarce in the Earth's crust. Cerium, one of the most common among them, is roughly as abundant as copper. Neodymium outstrips lead in average crustal concentration. What makes them functionally rare is that economically minable concentrations are uncommon, and once ore is extracted, separating individual elem…