Vladimirite is a rare
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
arsenate mineral
Arsenate minerals usually refer to the naturally occurring orthoarsenates, possessing the (AsO4)3− anion group and, more rarely, other arsenates with anions like AsO3(OH)2− (also written HAsO42−) (example: pharmacolite Ca(AsO3OH).2H2O) or (v ...
with a
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...
of Ca
5(HAsO
4)
2(AsO
4)
2·5H
2O. It is named after the Vladimirovskoye
deposit in
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
, where it was discovered in the 1950s.
Vladimirite is
monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...
-prismatic, which means crystallographically, it contains three axes of unequal length and the angles between two of the axes are 90 degrees, and one is less than 90 degrees. It belongs to the space group P2
1/c. The mineral also has an orthorhombic
polytype
In materials science, polymorphism describes the existence of a solid material in more than one form or crystal structure. Polymorphism is a form of isomerism. Any crystalline material can exhibit the phenomenon. Allotropy refers to polymorphism ...
. In terms of its optical properties, vladimirite is anisotropic which means the velocity of light varies depending on direction through the mineral. Relief is a diagnostic characteristic of a mineral in plane polarized light that refers to the various ways different minerals "stand out". Vladimirite's calculated relief is 1.65-1.661, which is moderate. It is colorless in plane polarized light, and it is weakly pleochroic. Pleochroism is the variety of colors under plane polarized light displayed by crystals at various angles.
Occurrence
Vladimirite was first described in 1953 at two deposits in Russia, the Khovu-Aksy nickel-cobalt deposit,
Tuva Republic
Tuva (; russian: Тува́) or Tyva ( tyv, Тыва), officially the Republic of Tuva (russian: Респу́блика Тыва́, r=Respublika Tyva, p=rʲɪˈspublʲɪkə tɨˈva; tyv, Тыва Республика, translit=Tyva Respublika ...
, and the Vladimirovskoye cobalt deposit,
Altai Mountains
The Altai Mountains (), also spelled Altay Mountains, are a mountain range in Central Asia, Central and East Asia, where Russia, China, Mongolia and Kazakhstan converge, and where the rivers Irtysh and Ob River, Ob have their headwaters. The m ...
,
Altaiskii Krai Altaysky (masculine), Altayskaya (feminine), or Altayskoye (neuter) may refer to:
*Altai Krai (''Altaysky Krai''), a federal subject of Russia
*Altaysky District, name of several districts in Russia
*Altaysky (rural locality) (''Altayskaya'', ''Alta ...
, Siberia.
[
It is a secondary mineral in the ]oxidized
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 a d ...
zone of arsenic-bearing ore
Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2 ...
deposits. It occurs with picropharmacolite
Picropharmacolite, Ca4Mg(AsO3OH)2(AsO4)2·11H2O, is a rare arsenate mineral. It was named in 1819 from the Greek for bitter, in allusion to its magnesium content, and its chemical similarity to pharmacolite. The mineral irhtemite, Ca4Mg(AsO3OH) ...
, erythrite
Erythrite or red cobalt is a secondary hydrated cobalt arsenate mineral with the formula . Erythrite and annabergite, chemical formula , or nickel arsenate form a complete series with the general formula .
Erythrite crystallizes in the monoclin ...
and aragonite
Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including prec ...
. It has been reported from the Richelsdorf Mountains, Hesse
Hesse (, , ) or Hessia (, ; german: Hessen ), officially the State of Hessen (german: links=no, Land Hessen), is a States of Germany, state in Germany. Its capital city is Wiesbaden, and the largest urban area is Frankfurt. Two other major histor ...
, Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
; the Bou Azzer district, Morocco
Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...
and the Mohawk mine, Keweenaw County, Michigan
Keweenaw County (, ; , ) is a county in the Upper Peninsula of the U.S. state of Michigan, the state's northernmost county. As of the 2020 United States Census, the population was 2,046, making it Michigan's least populous county. It is also the ...
.[
]
References
Calcium minerals
Arsenate minerals
Monoclinic minerals
Minerals in space group 14
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