Haidingerite is a

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 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 resem ...

mineral with formula Ca(AsO₃OH)·H₂O. It crystallizes in the

orthorhombic 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 a r ...

crystal system In crystallography, a crystal system is a set of point groups (a group of geometric symmetries with at least one fixed point). A lattice system is a set of Bravais lattices. Space groups are classified into crystal systems according to their po ...

as short prismatic to equant crystals. It typically occurs as scaly,

botryoidal A botryoidal ( ) texture or mineral habit, is one in which the mineral has an external form composed of many rounded segments, named for the Ancient Greek (), meaning "a bunch of grapes".Adjective form: ''botruoeidēs'' This is a common form fo ...

or fibrous coatings.http://rruff.geo.arizona.edu/doclib/hom/haidingerite.pdf Mineral Data Publishing, ''Handbook of Mineralogy'' It is soft,

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 th ...

of 2 to 2.5, and has a

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 (molecule), wa ...

of 2.95. It has

refractive indices In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or ...

of nα = 1.590, nβ = 1.602 and nγ = 1.638.http://www.mindat.org/min-1797.html Mindat with location data It was originally discovered in 1827 in Jáchymov,

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...

. It was named to honor

Austrian Austrian may refer to: * Austrians, someone from Austria or of Austrian descent ** Someone who is considered an Austrian citizen, see Austrian nationality law * Austrian German dialect * Something associated with the country Austria, for example: ...

mineralogist Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proces ...

Wilhelm Karl Ritter von Haidinger Wilhelm Karl Ritter von Haidinger (or Wilhelm von Haidinger, or most often Wilhelm Haidinger) (5 February 179519 March 1871) was an Austrian mineralogist. Early life Haidinger's father was the mineralogist Karl Haidinger (1756–1797), who died w ...

(1795–1871).http://www.webmineral.com/data/Haidingerite.shtml Webmineral data It occurs as a dehydration product of

pharmacolite Pharmacolite is an uncommon calcium arsenate mineral with formula CaHAsO4·2(H2O). It occurs as soft, white clusters of fibrous crystals and encrustations which crystallize in the monoclinic system. It is the arsenate analogue of the sulfate gypsum ...

in the

Getchell Mine The Getchell Mine is an underground gold mine in the Potosi Mining District of Humboldt County, Nevada, on the east flank of the Osgood Mountains, 35 miles northeast of Winnemucca. Prospectors Edward Knight and Emmet Chase discovered gold in ...

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

References

* Palache, C., H. Berman, and C. Frondel (1951) ''Dana’s system of mineralogy'', (7th edition), v. II, pp.708–709. Calcium minerals Arsenate minerals Orthorhombic minerals Minerals in space group 60 {{mineral-stub

See also

References