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Fingerite

Fingerite
General
Category Vanadate mineral
Formula
(repeating unit)
β-Cu2V2O5
Strunz classification 8.BB.80
Crystal system Triclinic
Crystal class Pinacoidal (1)
H-M symbol: (1)
Space group P1
Unit cell a = 8.16, b = 8.27
c = 8.04 [Å]; α = 107.14°
β = 91.39°, γ = 106.44°; Z = 1
Identification
Color Black; medium gray in reflected light
Crystal habit Subhedral or anhedral; equant or platelike; up to 150 μm
Cleavage None
Luster Metallic
Streak Dark reddish brown
Diaphaneity Opaque
Density 4.78
Optical properties Biaxial
References

Fingerite is a copper vanadate mineral with formula: β-Cu2V2O5. It was discovered as triclinic crystals occurring as volcanic sublimates around fumaroles in the crater of the Izalco Volcano, El Salvador.

Associated minerals include thenardite, euchlorine, stoiberite, shcherbinaite, ziesite, bannermanite, chalcocyanite and chalcanthite.

Fingerite is named for Larry W. Finger (b. 1940) of the Carnegie Institution.


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Wikipedia

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