Muscovite described by Art Smith, Mineralogist-Geologist wrote: I did a microscopic examination of the bead material that you call Muscovite. It is a natural stone, probably a metamorphic rock called quartzite. It is composed of well-fused grains of clear to slightly cloudy quartz with interspearsed flakes of pale tan, slightly iron stained, mica that is probably muscovite. The iron staining seems to be most concentrated on the edge of the muscovite flakes and so emphasizes them when the stone is polished. This is an excellent hard and durable stone that will make good beads, cabochons or other lapidary items.