An off-white pigment with complex reflective effects, mica is often used with transparent pigments to create mixed pigments with interference and pearlescent effects.
Mica is permanent and lightfast.
Although it is completely non-toxic and not bioreactive, fine particles may be irritating. This is of concern primarily for those exposed occupationally to dry mica powder. Breathing mica particles may cause lung fibrosis and pneumoconiosis.
Mica has been used as a pigment since prehistoric times.