Ziesite

Ziesite is a copper vanadate mineral with formula: β-Cu2V2O7. It was discovered in 1980 as monoclinic crystals occurring as volcanic sublimates around fumaroles in the crater of the Izalco Volcano, El Salvador. It is named after Emanuel George Zies (1883–1981), an American geochemist who studied Izalco in the 1930s.

Ziesite
General
CategoryVanadate mineral
Formula
(repeating unit)
β-Cu2V2O7
IMA symbolZie[1]
Strunz classification8.FA.10
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupA2/a
Unit cella = 7.68 Å, b = 8 Å
c = 10.09 Å; β = 110.27°; Z = 2
Identification
ColorBlack; reddish brown to dark reddish brown in transmitted light; white in reflected light
Crystal habitAnhedral crystals and incrustations
CleavageNone
LusterMetallic
StreakRed brown
DiaphaneityOpaque
Specific gravity3.86
Optical propertiesBiaxial
Refractive index2.055
References[2][3][4]

Closely related is blossite, also a copper vanadate with formula of α-Cu2V2O7. It forms orthorhombic crystals. Blossite was also first described for specimens from the Izalco volcano.

Ziesite and blossite are polymorphs, different crystal structure for the same chemical composition and are quite similar in physical properties.

Associated minerals include stoiberite, shcherbinaite, bannermanite, fingerite, mcbirneyite, blossite, chalcocyanite and chalcanthite.[2]

References


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