Descloizite is a rare mineral species consisting of basic lead

Lead

Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

 and zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

 vanadate

Vanadium

Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...

, , crystallizing in the orthorhombic

Orthorhombic crystal system

In crystallography, the orthorhombic crystal system is one of the seven lattice point groups. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a rectangular base and height , such that a,...

 system and isomorphous with olivenite

Olivenite

Olivenite is a copper arsenate mineral, formula Cu2AsO4OH. It crystallizes in the monoclinic system , and is sometimes found in small brilliant crystals of simple prismatic habit terminated by domal faces...

.

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

Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

 replacing vanadium

Vanadium

Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...

. Appreciable gallium

Gallium

Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...

 and germanium

Germanium

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. The isolated element is a semiconductor, with an appearance most similar to elemental silicon....

 may also be incorporated into the crystal structure.

Discovery and occurrence

It was discovered in the Sierra de Córdoba deposit in Córdoba

Córdoba, Argentina

Córdoba is a city located near the geographical center of Argentina, in the foothills of the Sierras Chicas on the Suquía River, about northwest of Buenos Aires. It is the capital of Córdoba Province. Córdoba is the second-largest city in Argentina after the federal capital Buenos Aires, with...

, Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

 in 1854 and named in honor of the French mineralogist Alfred Des Cloizeaux

Alfred Des Cloizeaux

Alfred Louis Olivier Legrand Des Cloizeaux 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 mineralogy at the École Normale Supérieure and afterwards at the Muséum National...

. It occurs as small prismatic or pyramidal crystals, usually forming drusy crusts

Druse (geology)

In geological usage druse or druzy is a coating of fine crystals on a rock fracture surface, vein or within a vug or geode.- Occurrence :Druse occurs worldwide, the most common is perhaps quartz druse within voids in chert or agates...

 and stalactitic aggregates; also as fibrous encrusting masses with a mammillary surface.

Descloizite occurs in oxidised

Redox

Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....

 portions of veins

Vein (geology)

In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation...

 of lead ores in association with pyromorphite

Pyromorphite

Pyromorphite is a mineral species composed of lead chlorophosphate: Pb53Cl, 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 planes, sometimes combined with narrow faces of a hexagonal...

, vanadinite

Vanadinite

Vanadinite is a mineral belonging to the apatite group of phosphates, with the chemical formula Pb53Cl. 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 found in the form of red hexagonal crystals. It is an uncommon...

, wulfenite

Wulfenite

Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found 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 sometimes called "yellow lead ore".It crystallizes...

, mottramite

Mottramite

Mottramite is an orthorhombic mineral, PbCu, at the copper end of the descloizite group. It was formerly called cuprodescloizite or psittacinite .-References:***...

, mimetite

Mimetite

Mimetite, whose name derives from the Greek Μιμητής mimethes, meaning "imitator", is an arsenate mineral 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...

 and cerussite

Cerussite

Cerussite is a mineral consisting of lead carbonate , and an important ore of lead. The name is from the Latin cerussa, white lead. Cerussa nativa was mentioned by Conrad Gessner in 1565, and in 1832 F. S. Beudant applied the name cruse to the mineral, whilst the present form, cerussite, is due to...

.

The Otavi Mountainland of northern Namibia

Namibia

Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...

 was once considered home to the greatest vanadium deposits in the world, including those at Berg Aukas, Abenab, Baltika and Uitsab. Descloizite and mottramite

Mottramite

Mottramite is an orthorhombic mineral, PbCu, at the copper end of the descloizite group. It was formerly called cuprodescloizite or psittacinite .-References:***...

 were the main ore minerals in each of these deposits, which are now exhausted. Other localities are the Sierra de Cordoba

Sierra de Córdoba

The Sierras de Córdoba is a mountain range in central Argentina, located between the Pampas to the east and south, the Chaco to the north and the foothills of the Andes to the west...

 in Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

; Lake Valley in Sierra County

Sierra County

Sierra County is the name of two counties in the United States:* Sierra County, California* Sierra County, New Mexico...

, New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

; Arizona

Arizona

Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

; Phoenixville in Pennsylvania

Pennsylvania

The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...

 and Kappel

Kappel

Kappel is a municipality in the district of Olten in the canton of Solothurn in Switzerland.-History:Kappel is first mentioned in 1260 as Capella. In 1312 it was mentioned as Nydern Capellen to distinguish it from the village of Oberkappelen which it today Kestenholz.-Geography:Kappel has an area,...

 (Eisen-Kappel) near Klagenfurt

Klagenfurt

-Name:Carinthia's eminent linguists Primus Lessiak and Eberhard Kranzmayer assumed that the city's name, which literally translates as "ford of lament" or "ford of complaints", had something to do with the superstitious thought that fateful fairies or demons tend to live around treacherous waters...

 in Carinthia

Carinthia (state)

Carinthia is the southernmost Austrian state or Land. Situated within the Eastern Alps it is chiefly noted for its mountains and lakes.The main language is German. Its regional dialects belong to the Southern Austro-Bavarian group...

.