(named for the French mineralogist C. L. Boulanger, died 1849), a mineral, a complex sulfide. Its chemical composition is Pb₅Sb₄S₁₁ Boulangerite crystallizes in a monoclinic system, forming greatly extended needlelike crystals or, more often, ray-shaped or stringy aggregates. Its color is silver gray to lead gray. Boulangerite has a hardness of 2.5-3.0 on the mineralogical scale, and its density is 6,230 kg/m³. It forms in ore veins of complex polymetallic formations. In the USSR there are deposits of boulangerite in Transbaikalia, Uzbekistan, and the Ukraine. Abroad, there are deposits in Czechoslovakia, the German Democratic Republic, France, Sweden, and the USA. Boulangerite is a secondary lead ore.