The clay body can contain black iron ores, flint, quartz, red iron ores, shale fragments, and white mica.
Later deformation has developed a cleavage with lenses of chlorite, quartz and white mica.
Broken glass shines like white mica in the vacant lots.
It is also sometimes called "black mica" as opposed to "white mica" (muscovite) - both form in some rocks, in some instances side-by-side.
Sericitic alteration is the process which causes the rock to be converted to the mineral sericite, which is a fine white mica.
For example, muscovite, a white mica, can be used for windows (sometimes referred to as isinglass), as a filler, or as an insulator.
Belt strata are composed primarily of fine-grained quartz and original clay (now metamorphosed to fine-grained white mica, or sericite).
Some brands contain powdered white mica, which acts as a mild abrasive, and also adds a cosmetically pleasing glittery shimmer to the paste.
Phyllite is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.
Some brands of toothpaste include powdered white mica.