Germanium is grey-white shiny, very brittle and has a high alkali, corrosion and acid resistance. It is a semiconductor element that is transparent to infrared-light.
Crystalline germanium is mainly used for lenses in the infrared optics, as they are applied in night-vision devices and thermal imaging cameras. Further applications of the metal are in the fields of electronics and solar as well as in luminescent material and metallurgy.
Due to the rapid rise in communication technology, germanium gains increasing importance for the manufacture of glass fibers.