Pure germanium  is a kind of gray white metal, glossy, hard, belonging to the carbon group.  Its chemical properties are similar to those of tin and silicon in the same group.  It is insoluble in water, hydrochloric acid, dilute caustic solution, aqua regia, concentrated nitric acid or sulfuric acid.  It is also stable in air. Germanium is amphoteric, so it is soluble in molten alkali, peroxide alkali, alkali metal nitrate or carbonate.Germanium metal is a semiconductor, mainly used in transistors, integrated circuits and various other electronic devices. Germanium's major end uses are in fiber-optic systems, infrared optics and in solar cell applications.High-purity germanium is a semiconductor material. It can be obtained by reduction of high-purity germanium oxide and smelting. Germanium single crystal doped with a small amount of specific impurities can be used to make various transistors, rectifiers and other devices. Germanium compounds are used in the manufacture of fluorescent plates and various high refractive index glasses.ATT is a professional supplier of high-purity germanium metal, in the forms of lumps, chucks, ingots, blocks and beads. The purity levels are 99.9% (3N), 99.99% (4N),99.999% (5N) , 99.9999% (6N)，99.99999% (7N).