Yttrium

Yttrium is a silvery metal that behaves much like the rare earths and is mined alongside them, mostly in China. It is one of four elements named after Ytterby, a small village in Sweden whose quarry yielded a string of new elements; Johan Gadolin identified its oxide in 1794.

In the television, yttrium becomes yttrium oxide, which is combined with aluminum oxide and a touch of cerium to make YAG phosphor, the yellow coating that turns blue LED light white. Yttrium compounds once made the red glow in tube televisions, and they also go into lasers, superconductors and tough zirconia ceramics.