Kaolin, also known as china clay, is a naturally occurring hydrated aluminum silicate mineral. It is a soft, white, plastic clay that is widely used in ceramics, papermaking, and as a pigment in paints, coatings, and plastics. Kaolin is valued for its fine particle size, purity, and ability to improve the brightness and opacity of materials. Its inert nature and high refractive index make it ideal for various industrial applications, including cosmetics and pharmaceuticals.