Valleriite

Uncommon sulfide-hydroxide mineral of iron and copper
(Fe2+,Cu)4(Mg,Al)3S4(OH,O)6Strunz classification2.FD.30Dana classification2.14.1.1Crystal systemTrigonal[1]Crystal classHexagonal scalenohedral (3m)
H-M symbol: (3 2/m)Space groupR3mUnit cella = 3.79, c = 34.1 [Å]; Z = 2IdentificationColorBronze-yellow, grayCrystal habitMassive, nodular, encrustations, thin splinteryCleavageExcellent on {0001}Mohs scale hardness1–1.5LusterMetallicStreakBlackDiaphaneityOpaqueSpecific gravity3.14 (measured)PleochroismStrong; pale yellow to deep brownReferences[2][3][1]

Valleriite is an uncommon sulfide mineral (hydroxysulfide) of iron and copper with formula: 4(Fe,Cu)S·3(Mg,Al)(OH)2[3] or (Fe2+,Cu)4(Mg,Al)3S4(OH,O)6.[2] It is an opaque, soft, bronze-yellow to brown mineral which occurs as nodules or encrustations.

Discovery and occurrence

Valleriite was first described in 1870 from an occurrence in Västmanland, Sweden. It was named for Swedish chemist Johan Gottschalk Wallerius (Vallerius) (1709–1785).

Valleriite occurs in dunites and chromitites replacing chalcopyrite in Cyprus. In Phalaborwa, South Africa it occurs as replacement of magnetite in a carbonatite. It occurs as replacements of copper and nickel phases in serpentinites and other altered ultramafic rocks.[3]

References

  1. ^ a b Valleriite data on Webmineral
  2. ^ a b Valleriite on Mindat.org
  3. ^ a b c Handbook of Mineralogy


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