Proustite

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Proustite
Proustite-209739.jpg
General
Category Sulfosalt minerals
Formula
(repeating unit)		Ag3AsS3
IMA symbol Prs [1]
Strunz classification 2.GA.05
Neso-sulfarsenites
Dana classification 03.04.01.01
Proustite group
Crystal system Trigonal
Crystal class Hexagonal scalenohedral (3m)
H-M Symbol: (3 2/m)
Space group R3c
Unit cell a = 10.79  Å, c = 8.69 Å; Z = 6
Identification
ColorScarlet-vermilion
Crystal habit Crystals prismatic and scalenohedral, massive, compact
Twinning Common
Cleavage Distinct on {1011}
Fracture Conchoidal to uneven
Tenacity Brittle
Mohs scale hardness2 – 2.5
Luster Adamantine
Streak Vermilion
Diaphaneity Translucent, darkens when exposed to light
Specific gravity 5.57 measured, 5.625 calculated
Optical propertiesUniaxial (−)
Refractive index nω = 3.087 – 3.088 nε = 2.792
Birefringence δ = 0.295 – 0.296
Pleochroism Moderate; cochineal-red to blood-red
References [2] [3] [4]

Proustite is a sulfosalt mineral consisting of silver sulfarsenide, Ag3 As S 3, known also as ruby blende , light red silver, arsenic-silver blende or ruby silver ore, and an important source of the metal. It is closely allied to the corresponding sulfantimonide, pyrargyrite, from which it was distinguished by the chemical analyses of Joseph L. Proust (1754–1826) in 1804, after whom the mineral received its name.

Contents

The prismatic crystals are often terminated by the scalenohedron and the obtuse rhombohedron, thus resembling calcite (dog-tooth-spar) in habit. The color is scarlet-vermilion and the luster adamantine; crystals are transparent and very brilliant, but on exposure to light they soon become dull black and opaque. The streak is scarlet, the hardness 2 to 2.5, [5] and the specific gravity 5.57. Its transparency differs from specimen to specimen, but most are opaque or translucent. [6]

Proustite occurs in hydrothermal deposits as a phase in the oxidized and supergene zone. It is associated with other silver minerals and sulfides such as native silver, native arsenic, xanthoconite, stephanite, acanthite, tetrahedrite and chlorargyrite. [2]

Magnificent groups of large crystals have been found at Chañarcillo in Chile; other localities which have yielded fine specimens are Freiberg and Marienberg in Saxony, Joachimsthal in Bohemia and Sainte-Marie-aux-Mines in Alsace [ citation needed ].

Structure

Subunit of the proustite structure, showing the connectivity of Ag, As (violet), S. SubunitProustite.jpg
Subunit of the proustite structure, showing the connectivity of Ag, As (violet), S.
The structure of proustite can be viewed as the Ag derivative of [AsS3] . Proustite.jpg
The structure of proustite can be viewed as the Ag derivative of [AsS3] .

See also

Related Research Articles

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<span class="mw-page-title-main">Zoisite</span> Sorosilicate mineral

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<span class="mw-page-title-main">Astrophyllite</span> Hydrous potassium iron titanium silicate mineral

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<span class="mw-page-title-main">Staurolite</span> Reddish brown to black nesosilicate mineral

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<span class="mw-page-title-main">Cobaltite</span> Sulfide mineral composed of cobalt, arsenic, and sulfur

Cobaltite is a sulfide mineral composed of cobalt, arsenic, and sulfur, CoAsS. It naturally appears in the form of a tetartoid, a form of dodecahedron with chiral tetrahedral symmetry. Its impurities may contain up to 10% iron and variable amounts of nickel. Structurally, it resembles pyrite (FeS2) with one of the sulfur atoms replaced by an arsenic atom.

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<span class="mw-page-title-main">Zektzerite</span>

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<span class="mw-page-title-main">Trithioarsenite</span>

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<span class="mw-page-title-main">Marrite</span>

Marrite (mar'-ite) is a mineral with the chemical formula PbAgAsS3. It is the arsenic equivalent of freieslebenite (PbAgSbS3), but also displays close polyhedral characteristics with sicherite and diaphorite. Marrite was named in honor of geologist John Edward Marr (1857–1933) of Cambridge, England.

<span class="mw-page-title-main">Dyscrasite</span> Silver antimonide mineral

The silver antimonide mineral dyscrasite has the chemical formula Ag3Sb. It is an opaque, silver white, metallic mineral which crystallizes in the orthorhombic crystal system. It forms pyramidal crystals up to 5 cm (2.0 in) and can also form cylindrical and prismatic crystals.

<span class="mw-page-title-main">Pearceite</span>

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<span class="mw-page-title-main">Lautite</span>

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<span class="mw-page-title-main">Fülöppite</span>

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<span class="mw-page-title-main">Arsenic blende</span> Index of articles associated with the same name

Arsenic blende or Arsenblende — a trivial name that has partially fallen out of scientific use, used by mineralogists, as well as representatives of mining and craft professions in relation to at least two similar ore minerals — orpiment and realgar, in composition — arsenic sulfides.

References

  1. ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. 1 2 http://rruff.geo.arizona.edu/doclib/hom/proustite.pdf Handbook of Mineralogy
  3. ↑ http://www.mindat.org/min-3294.html Mindat.org
  4. ↑ http://www.webmineral.com/data/Proustite.shtml Webmineral
  5. ↑ "Proustite". www.mindat.org. Retrieved 2021-08-12.
  6. ↑ "Proustite Value, Price, and Jewelry Information". International Gem Society. Retrieved 2021-08-12.
  7. ↑ Engel, P.; Nowacki, W."Die Verfeinerung der Kristallstruktur von Proustit, Ag3As S3 und Pyrargyrit, Ag3SbS3" Neues Jahrbuch fuer Mineralogie. Monatshefte 1966, p181-p184

Wikisource-logo.svg This article incorporates text from a publication now in the public domain :  Chisholm, Hugh, ed. (1911). "Proustite". Encyclopædia Britannica . Vol. 22 (11th ed.). Cambridge University Press. p. 490.

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