Bismuth oxychloride is an inorganic bismuth compound with the formula BiOCl, appearing as a white to pearlescent crystalline powder. It is well known for its excellent light-reflecting and nacreous (pearl-like) properties, which make it especially valuable in cosmetic and pigment applications. Chemically, it is stable, has low solubility in water, and shows good thermal and chemical resistance. In addition to cosmetics, bismuth oxychloride is used in ceramics, coatings, and materials research.