Haidingerite is a

calcium Calcium is a chemical element; it has 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 it ...

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 ...

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 Lattice (group), lattices result from stretching a cubic crystal system, cubic lattice along two of its orthogonal pairs by two different factors, res ...

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 (an infinite array of discrete points). Space groups (symmetry groups ...

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 f ...

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 mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...

of 2 to 2.5, and has a

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

of 2.95. It has

refractive indices In optics, the refractive index (or refraction index) of an optical medium is the ratio of the apparent speed of light in the air or vacuum to the speed in the medium. The refractive index determines how much the path of light is bent, or refrac ...

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, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

. It was named to honor Austrian

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

Wilhelm Karl Ritter von Haidinger Wilhelm Karl Haidinger (5 February 179519 March 1871), ennobled as Wilhelm Ritter von Haidinger in 1864, was an Austrian mineralogist. Early life Haidinger's father was the mineralogist Karl Haidinger (1756–1797), who died when Wilhelm was o ...

(1795–1871).http://www.webmineral.com/data/Haidingerite.shtml Webmineral data It occurs as a dehydration product of pharmacolite in the Getchell Mine,

Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...

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