Chlorargyrite

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Chlorargyrite
Chlorargyrite-Embolite-rh3-10a.jpg
General
CategoryHalide
Formula
(repeating unit)
AgCl
Strunz classification3.AA.15
Crystal systemIsometric
Crystal classHexoctahedral (m3m)
H-M symbol (4/m 3 2/m)
Space groupFm3m
Identification
ColorColorless when fresh; alters to bright chartreuse-green, light yellow, light green, grey, violet-brown on exposure to light
Crystal habitMassive to columnar
FractureIrregular/uneven, sub-conchoidal
TenacitySectile
Mohs scale hardness1.5 - 2.5
LusterAdamantine, resinous, waxy
StreakWhite
Specific gravity5.556
Optical propertiesIsotropic
Refractive indexn = 2.071
References[1][2][3]

Chlorargyrite is the mineral form of silver chloride (AgCl).[4] Chlorargyrite occurs as a secondary mineral phase in the oxidation of silver mineral deposits, it crystallizes in the isometric - hexoctahedral crystal class. Typically massive to columnar in occurrence it also has been found as colorless to variably yellow cubic crystals; the color changes to brown or purple on exposure to light. It is quite soft with a Mohs hardness of 1 to 2 and dense with a specific gravity of 5.55. It is also known as cerargyrite and, when weathered by desert air, as horn silver. Bromian chlorargyrite (or embolite) is also common. Chlorargyrite is water-insoluble.

It occurs associated with native silver, cerussite, iodargyrite, atacamite, malachite, jarosite and various iron–manganese oxides.[2]

It was first described in 1875 for occurrences in the Broken Hill district, New South Wales, Australia; the name is from the Greek, chloros for "pale green" and Latin for silver, argentum.[3]

See also[edit]

References[edit]

  1. ^ Chlorargyrite data on Mindat.org
  2. ^ a b Handbook of Mineralogy
  3. ^ a b Chlorargyrite data on Webmineral
  4. ^ Chisholm, Hugh, ed. (1911). "Cerargyrite" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
  • Palache, C., H. Berman, and C. Frondel (1951) Dana’s system of mineralogy, (7th edition), v. II, pp. 11–15