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Star-like galena crystals from Stari Trg mine, Trepča, Kosovo

Unusual six- and twelve-edged star-like galena crystals were found on a hand specimen from Stari Trg mine, Trepča, Kosovo and their morphology and way of growth were described. This twinned crystals look like spinel law twins, however detailed studies revealed different way of intergrowth twinning. The cause for this star-like morphological unit is oriented growth of galena with pyrrhotite according to epitaxial overgrowth galena (001)[100] || pyrrhotite (0001)[10-10], what produce secondary twinning of galena crystals during late crystallization. Galena crystals have three possible orientations on pyrrhotite. Each of the oriented galena individual must satisfy crystallographic condition, that one pair of opposite galena hexahedral faces (upper and lower part of the “star”) has to be parallel with basal pinacoid faces of pyrrhotite crystal and at the same time one pair of hexahedral faces have to be parallel with prismatic faces of pyrrhotite.

star-like galena crystals; Stari Trg mine

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