Mimetite is a

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...

arsenate The arsenate ion is . An arsenate (compound) is any compound that contains this ion. Arsenates are salts or esters of arsenic acid. The arsenic atom in arsenate has a valency of 5 and is also known as pentavalent arsenic or As(V). Arsenate res ...

chloride The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride s ...

mineral (Pb₅(AsO₄)₃Cl) which forms as a secondary mineral in lead deposits, usually by the

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or ...

galena Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It cr ...

and

arsenopyrite Arsenopyrite ( IMA symbol: Apy) is an iron arsenic sulfide (FeAsS). It is a hard ( Mohs 5.5-6) metallic, opaque, steel grey to silver white mineral with a relatively high specific gravity of 6.1. When dissolved in nitric acid, it releases elem ...

. The name derives from the Greek Μιμητής ''mimetes'', meaning "imitator" and refers to mimetite's resemblance to the mineral pyromorphite. This resemblance is not coincidental, as mimetite forms a mineral series with pyromorphite () and with

vanadinite Vanadinite is a mineral belonging to the apatite group of phosphates, with the chemical formula Pb5( V O4)3 Cl. It is one of the main industrial ores of the metal vanadium and a minor source of lead. A dense, brittle mineral, it is usually ...

(). Notable occurrences are Mapimi, Durango,

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

and Tsumeb,

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

Properties

Mimetite is a lead chloride arsenate mineral with the composition . It is a secondary mineral, formed by oxidation of primary lead minerals in arsenic-bearing lead deposits. It typically forms short hexagonal crystals that are yellow to brown to orange in color, very brittle, moderately hard (

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by ...

3.5-4), and dense (

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its dens ...

7.24). It is distinctive for its lack of transparency, its resinous to adamantine luster, and its solubility in

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...

. Mimetite forms a complete solid solution series with pyromorphite, with phosphate () substituting for arsenate (). The two minerals are almost identical in their properties and can be difficult to distinguish except by laboratory tests. Pyromorphite is the more common mineral at most locales.

Campylite Campylite is a variety of the lead arsenate mineral mimetite which received the name from the Greek 'kampylos'- bent, on account of the barrel-shaped bend of its crystals. It has also been used as an alternate name for pyromorphite. It occurs in ...

is a name applied to mimetite or pyromorphite that crystallizes as distinctive barrel-shaped crystals forming curved hemispherical aggregates. Bellite is a name formerly applied to a chromium-bearing mimetite, or possibly a mixture of crocoite, mimetite and quartz, which forms attractive orange red crystals, but has been discredited as a distinct mineral species.

Occurrences

Mimetite is found in association with lead and arsenic minerals, including pyromorphite,

cerussite Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate (PbCO3), and is an important ore of lead. The name is from the Latin ''cerussa'', white lead. ''Cerussa nativa'' was mentioned by Conrad Gess ...

, hemimorphite, smithsonite,

anglesite Anglesite is a lead sulfate mineral with the chemical formula PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and ...

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), lust ...

, mottramite,

willemite Willemite is a zinc silicate mineral () and a minor ore of zinc. It is highly fluorescent (green) under shortwave ultraviolet light. It occurs in a variety of colors in daylight, in fibrous masses and apple-green gemmy masses. Troostite is a v ...

, and wulfenite. Good specimens have been reported from

Gila County, Arizona Gila County ( ) is in the central part of the U.S. state of Arizona. As of the 2020 census, the population was 53,272. The county seat is Globe. Gila County comprises the Payson, Arizona Micropolitan Statistical Area. Gila County contains ...

, US; Ojocaliente,

Zacatecas , image_map = Zacatecas in Mexico (location map scheme).svg , map_caption = State of Zacatecas within Mexico , coordinates = , coor_pinpoint = , coordinates_footnotes = , subdivision_type ...

, Mexico; Cumberland, England;

Johanngeorgenstadt Johanngeorgenstadt () is a mining town in Saxony’s Ore Mountains, 17 km south of Aue, and 27 km northwest of Karlovy Vary. It lies in the district of Erzgebirgskreis, on the border with the Czech Republic, is a state-recognized heal ...

Saxony Saxony (german: Sachsen ; Upper Saxon: ''Saggsn''; hsb, Sakska), officially the Free State of Saxony (german: Freistaat Sachsen, links=no ; Upper Saxon: ''Freischdaad Saggsn''; hsb, Swobodny stat Sakska, links=no), is a landlocked state of ...

, Germany;

; and Broken Hill, Australia.

Mimetite specimen gallery

File:Mimetite-119809.jpg, Botryoidal mimetite in a vug in limonite matrix File:Mimetite-cktsu-48a.jpg, Cluster of translucent, golden mimetite crystals File:Mimetite-289052.jpg, Spherical aggregates of botryoidal mimetite File:Mimetite-176701.jpg, Mimetite, Pingtouling Mine, Guangdong Province, China. Size: 2.2 x 2.1 x 1.8 cm

References

External links

*{{cite EB1911, wstitle=Mimetite , volume=18 , short=x
Mineral Galleries
Lead minerals Halide minerals Arsenate minerals Hexagonal minerals Minerals in space group 176 Luminescent minerals