Akcesorický schreyerit ve vanadem bohatém grafitickém kvarcitu z Bítovánek (moldanubikum, západní Morava)Článek v PDF
Accesory schreyerite in vanadium-rich graphite quartzite at Bítovánky (Moldanubicum, western Moravia)
A new occurrence of schreyerite was found in graphite quartzite near Bítovánky, in the south-eastern part of the Moldanubian zone (Bohemian Massif). It forms thin lamellae and grains intergrown with vanadium-rich rutile (0.044–0.058 apfu V) and isolated microscopic grains, in mineral assemblage quartz + graphite + vanadium muscovite + vanadium dravite. Schreyerite is poor in Cr and its chemical composition corresponds to the formula (V3+1.890–1.980Cr3+0.020–0.040Al3+0.020–0.040)2(Ti4+2.810–2.850 V4+0.140–0.190)3 O9. Schreyerite is locally altered to hydrated TiO2 with higher contents of Al (≤ 0.060 apfu) and Fe (< 0.028 apfu) compared to the original phase. Schreyerite predominately formed by exsolution from vanadium-rich rutile in the metamorphic post-peak conditions of the upper amphibolite facies.
Stanislav Houzar*, Jan Cempírek, Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno, Czech Republic. *email@example.com