Germanium is a lustrous, hard-brittle, grayish-white metalloid in the carbon group.
Core Principles & Analysis
Clemens Winkler discovered germanium in the mineral argyrodite in 1886, and its properties fit Mendeleev's predicted 'eka-silicon' with striking precision.
The brittle gray metalloid is a semiconductor and is transparent to infrared light.
The first transistor, built at Bell Labs in 1947, was germanium, and today the element dopes fiber-optic cores, forms infrared lenses for night vision, and catalyzes PET plastic production.