Germanium

Germanium is a hard, brittle, grayish-white metalloid. Dmitri Mendeleev predicted it in 1871, and Clemens Winkler found it in 1886, naming it after Germany. It is recovered in small amounts from zinc ores and from the ash of burned coal.

The first transistor, built at Bell Labs in 1947, was made of germanium, and early electronics relied on it until silicon took over. Today it is added to the glass core of fiber-optic cables, and it is used in lenses for infrared and night-vision cameras because infrared light passes through it. It is also mixed with silicon in some high-speed chips and used in solar cells on satellites.