Interesting supergene Pb-rich mineral association from the Rovnost mining field, Jachymov (St. Joachimsthal), Czech Republic
Abstrakt
Rich supergene mineral association with prevalence of Pb was found in a shallow gallery of the Rovnost mine, the Jachymov (St. Joachimsthal) ore district, western Bohemia (Czech Republic).
Mimetite occurs as colourless transparent flexible fibres up to 1 mm in length. The fibres form greyish white aggregates grown on the surface of gangue strongly affected by supergene alteration.
The results of the single crystal X-ray diffraction study of mimetite with R(1) = 0.0381 are fully consistent with data reported previously for this mineral phase. According to electron microprobe study, interesting are namely elevated contents of SiO4 (up to 0.16 apfu).
Among the supergene minerals, cerussite, anglesite, wulfenite, philipsbornite-segnitite minerals, pyromorphite and metazeunerite were determined based on powder X-ray diffraction and electron microprobe analyses. This mineral assemblage is considered to be a result of a long-term in-situ weathering in near-surface conditions.