Muscovite is the most common member of the Mica group, but was not included in older lapidaries, texts that describe gemstones and their powers. The modern name Muscovite comes from the term “Muscovy Glass” which dates back to Elizabethan England. During that time period, mines near Moscow, Russia were producing long sheets of Muscovite that could be split into very thin slices. Some of these slices were nearly transparent and either clear white or lightly tinted. As a result, Muscovite was used as window panes and was a cheaper alternative to glass. The first known use of the term, Muscovy Glass can be found in a letter from the English Ambassador to the Russian Tsar Ivan the Terrible in 1568.
Today, Muscovite is an important mineral highly sought after by the mining industry. Mica can be found in igneous, sedimentary and metamorphic rocks. Most of it is ground up and used for a variety of industrial purposes. It is commonly used in construction and can be found in paint, plastic, rubber, and asphalt. Muscovite is also used in cosmetics. The more rare and expensive, thin sheets of Muscovite are used primarily to insulate specialty electronic parts, ranging from oxygen breathing equipment to radar systems. However, the main drive pushing Muscovite mining is the demand for ground mica for use in drilling mud for oil and and gas drilling.