Mottramite from the gallery Elizabeth in Černý Důl in Krkonoše Mountains (Czech Republic)
Article PDFMottramite from the gallery Elizabeth in Černý Důl in Krkonoše Mountains (Czech Republic)
Rare Pb-Cu vanadate, mottramite, was found at samples from the gallery Elizabeth in Černý Důl, Krkonoše Mountains (Czech Republic). It forms yellow to yellow-orange coatings and thin crusts formed by hemisperical aggregates with size up to 0.05–0.1 mm with vitreous lustre. Mottramite is orthorhombic, space group Pnma, the unit-cell parameters refined from X-ray powder diffraction data are: a 7.627(2), b 5.971(2), c 9.466(3) Å and V 431.1(1) Å3. Three chemically different types of mottramite were to distinguished on the base of occupation of B– and T-sites of ideal formula AB(XO4)(OH). The first is As-poor mottramite with empirical formula (Pb0.93Ca0.05) Σ0.98(Cu0.62Fe0.16Zn0.09)Σ0.87 (VO4)0.80 (PO4)0.09 (SiO4)0.08 (AsO4)0.02 (OH)0.63. The other two types are As-rich mottramite with different range of Fe and Zn substitution at B-site and empirical formula (Pb0.75Ca0.11Bi0.03)Σ0.89 (Cu0.78Fe0.05Zn0.04)Σ0.87 (VO4)0.51 (AsO4)0.32 (SiO4)0.12 (PO4)0.05 (OH)0.44 and (Pb0.82Ca0.12)Σ0.94 (Cu0.34Zn0.27Fe0.18)Σ0.79 (VO4)0.56 (AsO4)0.40 (SiO4)0.03 (PO4)0.01 (OH)0.42, respectively.
Petr Pauliš, Smíškova 564, 284 01 Kutná Hora; Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, 193 00 Prague 9-Horní Počernice
Jiří Sejkora, Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, 193 00 Prague 9-Horní Počernice; e-mail: jiri.sejkora@nm.cz
Petr Janák, Ulrichovo nám., 854, 500 02 Hradec Králové
Zdeněk Dolníček, Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, 193 00 Prague 9-Horní Počernice
Radko Tásler, Czech Speleological Society, ZO 5-02 Albeřice, Stará alej 462, 542 24 Svoboda nad Úpou
Ondřej Pour, Czech Geological Survey, Geologická 6, 152 00 Praha 5