Micas form a group of minerals easily recognizable for their cleavage, which allows them to split into definite crystallographic structural planes, as thin as a piece of paper. Micas are generally found in nature as small crystals in granite and metamorphic rocks. The word ‘mica’ is thought to mean ‘to shine’, referring to these minerals’ brightness. Besides its insulating properties, it has a sebum-regulator and soothing action. For its peculiar brightness it is used in the cosmetic production of eyeshadows, lipsticks and foundations.