Mica Sericite is a type of mica mineral that is composed of very fine-grained Muscovite. It is a soft, platy mineral that is often used as a filler in paint, plastics, Rubber, masterbatch, paper and other products. It is also used in cosmetics, as a pigment. In cosmetics, Sericite mica is used as a filler and extender, and to add shimmer and sparkle to products. In paint, it is used as a filler and extender, and to improve the flow and leveling of the paint. In plastics, it is used as a filler and extender, and to improve the strength and flexibility of the plastic. In rubber, it is used as a reinforcing agent, and to improve the strength and flexibility of the rubber. In paper, it is used as a filler and extender, and to improve the opacity and brightness of the paper