Snow-white ultramicro-fibrous compact gearksutite agregate. It was formed during interaction of HF (produced by pyrite oxidation in fluorite matrix) with concretion of allophane or caoline into quartz-muscovite greisen. Associating minerals are quartz crystals and muscovite, forming crust of the concretion. Specimen size is 4x2x1.5 cm. Collected by Lidia P. Ermilova in August of 1958 on dumps of vein #1 of the deposit. Pavel M. Kartashov collection and photo.
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