Chemistry:Canfieldite

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Canfieldite
Canfieldite-21373.jpg
Canfieldite
General
CategorySulfide minerals
Formula
(repeating unit)
Ag8SnS6
Strunz classification2.BA.70
Crystal systemOrthorhombic
Crystal classPyramidal (mm2)
(same H-M symbol)
Space groupPna21
Identification
ColorSteel gray with reddish tint
FractureIrregular/ uneven, conchoidal
TenacityBrittle
Mohs scale hardness2 12
|re|er}}Metallic
StreakGreyish black
DiaphaneityOpaque
Density6.2 – 6.3 g/cm3
References[1][2][3]

Canfieldite is a rare silver tin sulfide mineral with formula: Ag8SnS6. The mineral typically contains variable amounts of germanium substitution in the tin site and tellurium in the sulfur site. There is a complete series between canfieldite and its germanium analogue, argyrodite. It forms black orthorhombic crystals which often appear to be cubic in form due to twinning. The most typical form is as botryoidal rounded grape-like masses. Its Mohs hardness is 2.5 and the specific gravity is 6.28. Canfieldite exhibits conchoidal fracturing and no cleavage.

Canfieldite was first described in 1893 from an occurrence in Colquechaca, Potosí Department, Bolivia. It was named for Frederick Alexander Canfield (1849–1926), an American mining engineer.

See also

References

  1. Mineralienatlas
  2. Mindat with location data
  3. Webmineral data
  4. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode2021MinM...85..291W.