Note: The important species of the mica group are:
{muscovite}, common or potash mica, pale brown or
green, often silvery, including {damourite} (also
called {hydromica}); {biotite}, iron-magnesia mica,
dark brown, green, or black; {lepidomelane}, iron,
mica, black; {phlogopite}, magnesia mica, colorless,
yellow, brown; {lepidolite}, lithia mica, rose-red,
lilac. Mica (usually muscovite, also biotite) is an
essential constituent of granite, gneiss, and mica
slate; {biotite} is common in many eruptive rocks;
{phlogopite} in crystalline limestone and serpentine.
{Mica diorite} (Min.), an eruptive rock allied to diorite but
containing mica (biotite) instead of hornblende.
{Mica powder}, a kind of dynamite containing fine scales of
mica.
{Mica schist}, {Mica slate} (Geol.), a schistose rock,
consisting of mica and quartz with, usually, some
feldspar.