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Rammelsbergite

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Rammelsbergite
General
CategoryMineral
Formula
(repeating unit)
NiAs2
IMA symbolRmb[1]
Strunz classification2.EB.15a
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPnnm
Unit cella = 4.759 Å, b = 5.797 Å
c = 3.539 Å; Z = 2
Identification
ColorTin white with a faint pinkish hue
Crystal habitRarely as prismatic crystals; commonly massive, granular, radial, fibrous
TwinningOn {101}
CleavageDistinct on {101}
FractureIrregular
TenacityBrittle
Mohs scale hardness5.5–6
LusterMetallic
StreakGrayish black
DiaphaneityOpaque
Specific gravity7.0–7.1
Optical propertiesStrongly anisotropic
PleochroismWeak, yellow to pinkish hue and bluish white
References[2][3][4]

Rammelsbergite is a nickel arsenide mineral with formula NiAs2. It forms metallic silvery to tin white to reddish orthorhombic prismatic crystals, and is usually massive in form. It has a Mohs hardness of 5.5 and a specific gravity of 7.1.

It was first described in 1854 from its type locality in the Schneeberg District in Saxony, Germany. It was named after the German chemist and mineralogist, Karl Friedrich August Rammelsberg (1813–1899).[3]

It occurs as a hydrothermal mineral in medium temperature veins association with skutterudite, safflorite, lollingite, nickeline, native bismuth, native silver, algodonite, domeykite and uraninite.[2]

See also

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References

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  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. ^ a b Handbook of Mineralogy
  3. ^ a b Mindat.org
  4. ^ Webmineral data