Erbium

Erbium is a silvery rare-earth metal discovered by Carl Gustaf Mosander in 1843 and named after Ytterby, the Swedish village whose quarry gave its name to four elements. It is mined with other rare earths, mainly in China.

Erbium quietly powers the internet. Light traveling through glass optical fibers fades over long distances. A short length of fiber laced with erbium, energized by a laser, boosts the signal directly as light, with no need to convert it to electricity and back. These amplifiers sit along undersea cables and long-haul links. Erbium also makes lasers for skin and dental treatments, and its compounds give glass and gemstones a soft pink color.