Scorodite

Scorodite is a common hydrated iron arsenate mineral, with the chemical formula FeAsO4·2H2O. It is found in hydrothermal deposits and as a secondary mineral in gossans worldwide. Scorodite weathers to limonite.

Scorodite
General
CategoryArsenate minerals
Formula
(repeating unit)
FeAsO4·2H2O
IMA symbolScd[1]
Strunz classification8.CD.10
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPcab
Unit cella = 8.937 Å, b = 10.278 Å
c = 9.996 Å; Z = 8
Identification
ColorGreen, blue-green, grey, grayish-green, blue, yellow-brown, nearly colorless, violet
FractureSub-Conchoidal
Mohs scale hardness3.5-4
LusterSub-Adamantine, Vitreous, Resinous
StreakGreenish-White
DiaphaneityTranslucent
Densitymeasured: 3.27 g/cm3 calculated: 3.276 g/cm3
Optical propertiesBiaxial (+)
PleochroismWeak
2V angleMeasured: 40° to 75° Calculated: 46° to 80°
Dispersionrelatively strong r > v
References[2]

Scorodite was discovered in Schwarzenberg, Saxony, Germany. Named from the Greek Scorodion, "garlicky". When heated it smells of garlic, which gives it the name.

References

Further reading

  • Palache, C., H. Berman, and C. Frondel (1951) Dana's system of mineralogy, (7th edition), v. II, pp. 763–767


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