Descloizite is a rare mineral species consisting of basic

lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

and

zinc Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...

vanadate In chemistry, a vanadate is an anionic coordination complex of vanadium. Often vanadate refers to oxoanions of vanadium, most of which exist in its highest oxidation state of +5. The complexes and are referred to as hexacyanovanadate(III) and no ...

, , crystallizing in the

orthorhombic crystal system In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with ...

and isomorphous with

olivenite Olivenite is a copper arsenate mineral, formula Cu2 As O4O H. It crystallizes in the monoclinic system (pseudo-orthorhombic), and is sometimes found in small brilliant crystals of simple prismatic habit terminated by domal faces. More commonly ...

. Appreciable

gallium Gallium is a chemical element; it has Chemical symbol, symbol Ga and atomic number 31. Discovered by the French chemist Paul-Émile Lecoq de Boisbaudran in 1875, elemental gallium is a soft, silvery metal at standard temperature and pressure. ...

and

germanium Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically ...

may also be incorporated into the crystal structure. The color is deep cherry-red to brown or black, and the crystals are transparent or translucent with a greasy lustre; the streak is orange-yellow to brown; specific gravity 5.9 to 6.2; hardness 31/2. A variety known as cuprodescloizite is dull green in color; it contains a considerable amount of copper replacing zinc and some

arsenic Arsenic is a chemical element; it has Symbol (chemistry), symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is not ...

replacing

vanadium Vanadium is a chemical element; it has Symbol (chemistry), symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an ...

. There is also an

arsenate The arsenate is an ion with the chemical formula . Bonding in arsenate consists of a central arsenic atom, with oxidation state +5, double bonded to one oxygen atom and single bonded to a further three oxygen atoms. The four oxygen atoms orien ...

analogue called arsendescloizite.

Discovery and occurrence

It was discovered in the Sierra de Córdoba deposit in

Córdoba Córdoba most commonly refers to: * Córdoba, Spain, a major city in southern Spain and formerly the imperial capital of Islamic Spain * Córdoba, Argentina, the second largest city in Argentina and the capital of Córdoba Province Córdoba or Cord ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

, in 1854 and named in honor of the French mineralogist

Alfred Des Cloizeaux Alfred Louis Olivier Legrand Des Cloizeaux (17 October 18176 May 1897) was a French mineralogist. Des Cloizeaux was born at Beauvais, in the department of Oise. He studied with Jean-Baptiste Biot at the Collège de France. He became professor of ...

(1817–1897). It occurs as small prismatic or pyramidal crystals, usually forming drusy crusts and stalactitic aggregates; also as fibrous encrusting masses with a mammillary surface. Descloizite occurs in

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

portions of

veins Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal c ...

of lead ores in association with

pyromorphite Pyromorphite is a mineral species composed of lead chlorophosphate: Pb5( P O4)3 Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common, and have the form of a hexagonal prism terminated by the basal p ...

vanadinite Vanadinite is a mineral belonging to the apatite group of Phosphate minerals, phosphates, with the chemical formula lead, Pb5(vanadium, Voxygen, O4)3chlorine, Cl. It is one of the main industrial ores of the metal vanadium and a minor source of ...

wulfenite Wulfenite is a lead molybdate mineral with the formula Pb Mo O4. It often occurs as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is some ...

mottramite Mottramite is an orthorhombic anhydrous vanadate hydroxide mineral, lead, Pbcopper, Cu(vanadium, Voxygen, O4)(Ohydrogen, H), at the copper end of the descloizite subgroup. It was formerly called cuprodescloizite or psittacinite (this mineral cha ...

mimetite Mimetite is a lead arsenate chloride mineral () which forms as a secondary mineral in lead deposits, usually by the Redox, oxidation of galena and arsenopyrite. The name derives from the Greek ''mimetes'', meaning "imitator" and refers to mimeti ...

and

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

. The Otavi ("O-tarvi") Mountainland of northern

Namibia Namibia, officially the Republic of Namibia, is a country on the west coast of Southern Africa. Its borders include the Atlantic Ocean to the west, Angola and Zambia to the north, Botswana to the east and South Africa to the south; in the no ...

was once considered home to the greatest vanadium deposits in the world, including those at Berg Aukas ("OW-cuss"), Abenab ("UB-en-ub"), Baltika ("BUL-tika") and Uitsab ("ATE-sub").Boni et al., 2007, Genesis of vanadium ores in the Otavi Mountainland, Namibia. Economic Geology v.102 p.441-469. Descloizite and mottramite were the main ore minerals in each of these deposits, which are now exhausted. Other localities are the Sierra de Cordoba in Argentina; Lake Valley in Sierra County,

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

;

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

;

Phoenixville Phoenixville is a Borough (Pennsylvania), borough in Chester County, Pennsylvania, United States. It is located northwest of Philadelphia, Pennsylvania, Philadelphia at the junction of French Creek (Schuylkill River tributary), French Creek an ...

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

and Obir,

Carinthia Carinthia ( ; ; ) is the southernmost and least densely populated States of Austria, Austrian state, in the Eastern Alps, and is noted for its mountains and lakes. The Lake Wolayer is a mountain lake on the Carinthian side of the Carnic Main ...

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

References

{{Commons category Vanadate minerals Zinc minerals Lead minerals Descloizite group Orthorhombic minerals Minerals in space group 62 Minerals described in 1854

Discovery and occurrence

See also

References