Micaceous sandstone, which is one of the primary types of sandstone, contains appreciable quantities of mica minerals. The most distinguishing characteristic of these minerals is their ability to be perfectly cleaved into thin, flexible sheets. The inclusion of the platy micas in sandstone deposits is readily apparent to the naked eye, making identification of hand samples of the rock relatively simple. Micaceous sandstones are typically found among rivers and lakes, and although any mica may be present in the rocks, the most common seems to be the light-colored mineral muscovite.