Phlogopite

  Phlogopite has synthetic phlogopite and natural phlogopite, natural phlogopite with dark phlogopite and light phlogopite.
  Phlogopite features: a complete cleavage of mica, yellow brown color and like golden the reflection. The difference with the muscovite is that decomposition in boiling sulfuric acid, while producing a species - milky solution, but muscovite can not. Most used in industry is muscovite, followed by phlogopite, the difference with biotite is that color in light. Phlogopite mainly in the ultra-basic rocks such as kimberlite, and dolomitic marble of the contact metamorphic zone. Impure magnesian limestone subjected to regional metamorphism, but also can be formed.
  Light-colored phlogopite is transparent with vitreous luster; dark phlogopite is translucent. Hardness 2 ─ 3. Proportion of 2.70 - 2.85, not conductive. In microscope transmitted light, it is colorless or brown yellow. Quality of pure phlogopite is the superior insulation in electrical industry, is also widely used in the lacquer coating.