Cerussite is a white mineral form of lead (II) carbonate (PbCO3), a major ore of lead, found in Mexico, Spain, southwest Africa, Australia, and Colorado, USA. It is formed by weathering (oxidation) of galena. It has prismatic or needle-shaped crystals (orthorhombic) that are usually colorless or white, but may be green or gray with a resinous or vitreous luster. White lead, used as a paint pigment, is a basic lead (II) carbonate (PbCO3 + Pb(OH)2). Hardness: 3–3.5; relative density 6.6.