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
Mineral Rock forming minerals – typically silicates or occasionally carbonates – have a specific gravity of 2.5–3.5. High specific gravity is a diagnostic property of a mineral. A variation in chemistry (and consequently, mineral class) correlates to a change in specific gravity. Among more common minerals, oxides and sulfides tend to have a higher specific gravity as they include elements with higher atomic mass. A generalization is that minerals with metallic or adamantine lustre tend to have higher specific gravities than those having a non-metallic to dull lustre. For example, hematite, FeO, has a specific gravity of 5.26 while galena, PbS,