Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities? After each set of pictures there should be some descriptive text. If none appears it means that we need someone to tell us about the specimens from that locality and something about the geology of the occurrence.
Thin sheets of muscovite (showing it's property of flexibility) are commonly available, but good examples of crystals are not particularly common. Almost all of the specimens are from pegmatites, with Brazil being the most prolific. Also sometimes sheets of muscovite with various inclusions are sold.
The earliest use of muscovite was for jewelry. The first major use of muscovite was as a window pane for wood and coal burning stoves. Currently sheet mica is used as an electrical insulator and in electronic capacitors. It is also used as a "glitter" component in cosmetics.
Muscovite is found in all types of rocks. It occurs as a detrital component in sandstones and arkoses, is a major component in metamorphic rocks (mica schists), as an accessory mineral in granites and pegmatites and the variety sericite is common in many hydrothermal deposits. Most commercial production is from large books in pegmatites.
The most common forms are hexagonal crystals, but you can also get star twins, and aggregates forming balls. The largest known crystal of muscovite came from the Purdy mica mine in Ontario Canada. It measured at least 2.4m long and 1.5m in diameter.