MINING ROCKSTAR OF THE WEEK – MUSCOVITE!!
Muscovite is the most common mineral of the mica family. It is an important rock-forming mineral present in igneous, metamorphic, and sedimentary rocks. Like other micas it readily cleaves into thin transparent sheets. Muscovite sheets have a pearly to vitreous lustre on their surface. If they are held up to the light, they are transparent and nearly colourless, but most have a slight brown, yellow, green, or rose-colour tint. The ability of muscovite to split into thin transparent sheets - sometimes up to several feet across - gave it an early use as window panes. In the 1700's it was mined for this use from pegmatites in the area around Moscow, Russia. These panes were called "muscovy glass" and that term is thought to have inspired the mineral name "muscovite." Sheet muscovite is an excellent insulator, and that makes it suitable for manufacturing specialized parts for electrical equipment. Scrap, flake, and ground muscovite are used as fillers and extenders in a variety of paints, surface treatments, and manufactured products. The pearlescent lustre of muscovite makes it an important ingredient that adds "glitter" to paints, ceramic glazes, and cosmetics - "Geology.com"