- A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. Pigments are typically solid and ground into fine powder. - Zinc oxide (ZnO) is a widely used white pigment known as Zinc White. - Chalk is primarily Calcium carbonate (CaCO₃), which is used as a white pigment and filler. - White lead (basic lead carbonate, (PbCO₃)₂·Pb(OH)₂) is a dense white pigment historically used in paints, although its use has declined due to toxicity. - Silica (Silicon dioxide, SiO₂) occurs in many forms. While very fine forms like fumed silica can act as opacifiers and contribute to whiteness and are used as fillers in paints, its primary applications often lie outside of being a dedicated coloring pigment, such as abrasives, drying agents, fillers for controlling rheology or structure, and as a component of glass or ceramics. Compared to the others, its role as a pigment is less central.