Chlorargyrite

(repeating unit)AgClIMA symbolCag[1]Strunz classification3.AA.15Crystal systemIsometricCrystal classHexoctahedral (m3m)
H-M symbol (4/m 3 2/m)Space groupFm3mIdentificationColorColorless when fresh; alters to bright chartreuse-green, light yellow, light green, grey, violet-brown on exposure to lightCrystal habitMassive to columnarFractureIrregular/uneven, sub-conchoidalTenacitySectileMohs scale hardness1.5–2.5LusterAdamantine, resinous, waxyStreakWhiteSpecific gravity5.556Optical propertiesIsotropicRefractive indexn = 2.071References[2][3][4]
Mineral form of silver chloride

Chlorargyrite is the mineral form of silver chloride (AgCl).[5] 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.[3]

It was first described in 1875 for occurrences in the Broken Hill district, New South Wales, Australia. The rich Bridal Chamber deposit at Lake Valley, Sierra County, New Mexico was almost pure chlorargyrite.[6] The name is from the Greek, chloros for "pale green" and Latin for silver, argentum.[4]

See also

Wikimedia Commons has media related to Chlorargyrite.

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. ^ Chlorargyrite data on Mindat.org
  3. ^ a b "Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2016-03-04. Retrieved 2017-04-24.
  4. ^ a b Chlorargyrite data on Webmineral
  5. ^ Chisholm, Hugh, ed. (1911). "Cerargyrite" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
  6. ^ O’Neill, J. Michael; et al. (2002). Geologic Investigations in the Lake Valley Area, Sierra County, New Mexico. Denver, CO: U.S. Department of the Interior, U.S. Geological Survey. Retrieved 3 February 2018.
  • Palache, C., H. Berman, and C. Frondel (1951) Dana's system of mineralogy, (7th edition), v. II, pp. 11–15


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