Minerální asociace a chemické složení Mg-wolframi tu a scheelitu z Cetoraze u Pacova, Česká republikaČlánek v PDF
Mineral assemblage and chemical composition of Mg-wolframite and scheelite from Cetoraz by Pacov, Czech Republic
Magnesium-bearing wolframite was analysed from the occurence near Cetoraz by Pacov. It forms grayish to black crystals up to 10 cm and irregular grains of various size. Wolframite composition is dominated in ferberite with average chemical composition (Fe0.752Mn0.227Mg0.040Ca0.001K0.001)Σ1.021(W0.987Nb0.004V0.004)Σ0.995O4. Unusual is relatively high huanzalaite component (up to 4 %) and increased content of Nb. Wolframite is replaced by scheelite with nearly ideal chemical composition CaWO4. Scheelite forms light yellow and light gray grains up to 1 cm and occurs in quartz or with wolframite. Both wolframite and mainly scheelite are strongly altered and sometimes fully replaced by mineral close to “ferritungstite”, which was previously misidentified as younger wolframite II. Further research is necessary due to uncertain structure and likely content of water in this secondary phase.
Lenka Losertová, Zbyněk Buřival, Zdeněk Losos, Institute of Geological Sciences, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic. e-mail: email@example.com, firstname.lastname@example.org, email@example.com
Stanislav Houzar, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic. e-mail: firstname.lastname@example.org