Zinkolivenit z rudního revíru Krupka, Krušné hory (Česká republika)

Pages 24-29
Bulletin mineralogicko-petrologického oddělení Národního muzea v Praze | 2008/16/1

Rare supergene Zn-Cu arsenate, zincolivenite, was found in remnants of mine dumps of the abandoned Stříbrná 2 adit at NW margin of the Krupka town, Krušné hory Mountains, northern Bohemia, Czech Republic. It forms coatings and crusts up to 1 cm2 which are rarely composed by hemispherical aggregates up to 0.1 - 2 mm in size. Tiny tabular crystals (up to 8 - 10 μm) were observed at their surface. Zincolivenite is translucent, light green with bluish or yellowish tint. White hydrozincite, colourless gypsum and red brown „limonite“ were found in the association. Zincolivenite is orthorhombic, space group Pnnm, the unit-cell parameters refined from X-ray powder data are: a = 8.456(2) b = 8.465(2), c = 5.986(1) Å, V = 428.9(1) Å3. Chemical analyses yielded the average composition CaO 0.11, FeO 0.38, PbO 1.00, CuO 17.45, ZnO 36.42, Al2O3 1.42, As2O5 39.70, P2O5 0.14, SO3 0.34, H2O (3.44), total (100.10) wt. %, corresponding to the formula (Zn1.27Cu0.62Al0.08Pb0.01Ca0.01)Σ1.99 [(AsO4)0.98(PO4)0.01(SO4)0.01]Σ1.00(OH)1.09 on the basis of 1 atom in anion site. Chemical composition of the studied zincolivenite is compared to published data. The origin of zincolivenite at Krupka is interpreted as the product of weathering of primary sulfides in conditions of mine dumps deposited at the earth surface.

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