The active two-level quarry (Kracík’s Quarry) between the villages of Kyje and Doubravice is opened in a belt of upper Paleozoic basaltandesite, stretching from Libuň as far as to Kozákov Hill. Three different lava flows are probably exposed here. The rock is markedly porphyritic in places, with melaphyre texture, hosting a very rich mineral assemblage: quartz and its coloured varieties, calcite, baryte, chalcedony, palygorskite, some of the zeolite-group minerals, limonite, goethite etc. The lower lava flow at the base of the quarry contains veins of brownish-yellow moss jasper – a mineral typical for this site. The quarry is renowned for its occurrences of gem stones. Its agates usually show wonderful colours of rather dark shades, with star-like druses of crystalline quartz in the centres.




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