Muscovite mineral Britannica
Muscovite, also called common mica, potash mica, or isinglass, abundant silicate mineral that contains potassium and aluminum. Muscovite is the most common member of the mica group. Because of its perfect cleavage, it can occur in thin, transparent, but durable sheets.Sheets of muscovite were used in Russia for windowpanes and became known as Muscovy glass (isinglass), hence its common name.
