Йорданка Минчева-Стефанова; Светослав Петрусенко; Маргарита Кръстева; Димитър Сокеров [Jordanka Minčeva-Stefanova; Svetoslav Petrussenko; Margarita Krusteva; Dimitar Sokerov]
29 December 2017 ·
volume 24 · pp. 121–126 ·
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Abstract: We studied calcite crystals from the ‘Surneshko Kladenche’ deposit of the Rossen ore district. They were formed in the cavities of calcite-chalcopyrite ore veins. The largest crystals reached 40 cm in length and 4–5 cm in thickness along the c-axis. They were observed in the upper parts of the veins. Their formation begins with crystallisation of the papierspaths with a lot of gas fluids. Later on, an oriented growth of platy monocalcite follows between the papierspath platelets, with a periphery of r {1011} faces. An oriented growth continues with numerous small, mainly rhombohedral, crystals on the free pinacoidal face and an overgrowth at the periphery of the {1011} face. The process ends with a peripheral scalenohedral growth of the platy crystals with the {3142}, {2131} and {2134} forms. The temperature of formation of 145—63 C suggests a genesis of calcite from low temperature hydrothermal solutions.
Keywords: calcite, crystal habit, crystallisation, inclusions, Rossen ore district