Quartz Crystal

Crystal system: hexagonal Department 
Chemical composition: SiO2 
Characteristics: good crystalline quartz are known as crystal, usually showed the six-party columns and rhombohedron posed by poly-shaped. Cylinder on the often striated, pure quality from colorless, transparent, glass luster, conchoidal fracture, hardness 7, the proportion of 2.65, including those impurity was purple, gold, TB, such as color. 
Occurrence: produced in the metamorphic rocks in the vicinity of their geological soil for green schist, graphite schist, sericite schist, sericite schist, green mud, quartz schist, crystalline limestone of interbedded, during which a lot of milky white quartz vein of, crystal that is produced in the cross section of the Green clay schist quartz vein the size of the hole crystal. 
Purposes: as semi-precious stones, Machinable for outside decorations, its optical properties for use in precision optical instruments, such as sub-photoelectron spectroscopy and optical lenses. Another according to their electrical characteristics of materials used in electronic communications, such as crystal oscillators, etc.; crystal produced by electric furnace melting of glass, small expansion coefficient, heat resistance, acid-resistant and have insulation suitable for the machine type of heating devices, as well as the manufacture of high pressure mercury and so on.