Zeolity z lomu Bernartice u Zruče nad Sázavou (Česká republika)Článek v PDF
Zeolites from the Bernartice quarry near Zruč nad Sázavou (Czech Republic)
An unusual zeolite mineralization was found in fissures and cavities of oligoclasite pegmatite hosted in serpentinite rocks in the active Bernartice quarry, 7 km S from Zruč nad Sázavou, central Bohemia, Czech Republic. The earliest thomsonite-Ca forms light grey acicular crystals, up to 10 mm in size, usually replaced by Mg-Al-Si-(Ca) saponite-like mineral. It is orthorhombic, space group Pncn, with unit-cell parameters refined from PXRD: a 13.108(4), b 13.068(3), c 13.244(4) Å and V 2268.6(9) Å3. Barium- and Mg-rich chabazite-Ca forms abundant white rhombohedral, cube-like crystals with vitreous lustre, up to 4 mm in size. It is trigonal, space group R-3m, with unit-cell parameters refined from PXRD: a 13.8055(12), c 14.967(2) Å and V 2470.4(5) Å3. The rare chabazite-Mg and chabazite-K form sometimes the youngest 30–40 μm thick margin of chabazite crystals. The youngest harmotome was observed as white prismatic crystals with vitreous lustre up to 0.5 mm in size. It is monoclinic, space group P21/m, with unit-cell parameters refined from PXRD: a 9.8581(16), b 14.1494(12), c 8.6854(11) Å, β 124.622(8)° and V 997.0(3) Å3. The quantitative chemical composition (by electron microprobe) for all studied zeolites are given.
Jiří Sejkora, Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, 193 00 Prague 9-Horní Počernice; e-mail: firstname.lastname@example.org
Petr Pauliš, Smíškova 564, 284 01 Kutná Hora; Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, 193 00 Prague 9-Horní Počernice
Zdeněk Dolníček, Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, 193 00 Prague 9-Horní Počernice
Jakub Plášil, Institute of Physics of the Czech Academy of Science, Na Slovance 1999/2, 182 21 Praha 8, Czech Republic
Radek Škoda, Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 2, 611 37, Brno, Czech Republic