Vauquelinite
From Infogalactic: the planetary knowledge core
Vauquelinite | |
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Vauquelinite
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General | |
Category | Phosphate mineral |
Formula (repeating unit) |
CuPb2(CrO4)(PO4)(OH) |
Strunz classification | 07.FC.05 |
Crystal symmetry | Monoclinic prismatic H-M symbol: (2/m) Space group: P 21/n |
Unit cell | a = 13.754(5) Å, b = 5.806(6) Å, c = 9.563(3) Å; β = 94.55°; Z=4 |
Identification | |
Color | Olive-green, apple-green, brown to nearly black |
Crystal habit | Irregular wedge shaped crystals, mammillary, reniform masses |
Crystal system | Monoclinic |
Twinning | Present on {102} |
Cleavage | Indistinct |
Fracture | Irregular |
Tenacity | Brittle |
Mohs scale hardness | 2.5 - 3 |
Luster | Adamantine, resinous |
Streak | Greenish or brownish |
Diaphaneity | Translucent |
Specific gravity | 6.16 |
Optical properties | Biaxial (-) |
Refractive index | nα = 2.110 nβ = 2.220 nγ = 2.220 |
Birefringence | δ = 0.110 |
Pleochroism | X = Light green, Y = Light brown, Z = Light brown |
2V angle | Near zero |
References | [1][2][3] |
Vauquelinite is a complex mineral with the formula CuPb2(CrO4)(PO4)(OH) making it a combined chromate and phosphate of copper and lead. It forms a series with the arsenate mineral fornacite.[1]
It was first described in 1818 in the Beryozovskoye deposit, Urals, Russia, and named for Louis Vauquelin (1763–1829), a French chemist.[1] It occurs in oxidized hydrothermal ore deposits and is associated with crocoite, pyromorphite, mimetite, cerussite, beudantite and duftite at the type locality in Russia.[3]
References
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