Mimetite Mimetite Mimetite, whose name derives from the Greek Μιμητής "mimetes", meaning "imitator", is a lead arsenate chloride mineral (Pb(AsO)Cl) which forms as a secondary mineral in lead deposits, usually by the oxidation of galena and arsenopyrite. The name is a reference to mimetite's resemblance to the mineral pyromorphite. This resemblance is not coincidental, as mimetite forms a mineral series with pyromorphite (Pb()) and with vanadinite (Pb()). Notable occurrences are Mapimi, Durango, Mexico and Tsumeb, Namibia. Industrially, mimetite is a minor ore of lead. The chief use of mimetite is as a collector's specimen, often creating attractive botryoidal crusts on the
Broken Hill ore deposit hornblende schists. The ore consists of massive, recrystallised sphalerite-rich, galena-sphalerite and galena-rich sulfide lenses in folded horizons, known as No. 2 Lens Formation and No.3 Lens Formation. Both have distinctive metal ratios and gangue minerals. The ore boundaries are parallel to the bedding planes. According to Gustafson, "There is evidence that the ore has been introduced into an old, already folded, rock and has replaced certain favourable layers of that rock, particle by particle, with large tonnages of garnet, rhodonite, fluorite, marmatite (and wurtzite), galena, and other minerals that constitute the orebodies." The Potosi-Footwall Gneiss is found on both sides