Characteristics: Shiny, reflective, dark silvery gray metalloid, pure germanium is a 'p-type' semiconductor. Conductivity depends largely on added impurities. Attacked by nitric acid and aqua regia, but stable in water, acids, and alkalies in absence of dissolved oxygen. Low toxicity. Germanium is too brittle and hard to be rolled or drawn.
Germanium is principally used as a semiconductor material for transistors. The first generation of semiconductors were based solely on germanium, then lower-cost silicon was used. Later, silicon-germanium alloys were developed. Due to its optical properties, germanium is used in fiber-optics, infrared optics and in solar cell applications.