Selenium secondaries from Zálesí

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Created on Monday, 19 August 2013 19:15

Last Updated on Monday, 19 August 2013 19:15

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Selenium secondaries from Zálesí

Zálesí is worldwide good known locality of uranium mineralisation in Rychlebské Mts (NE part of the Czech Republic). It belongs between Czech most important uranium minerals localities, but Czech best erythrites and high quality arsenides were also found here. After the mining period was gradually found attractive association of the secondary selenium minerals.

Selenium minerals were found almost exclusively on the outcrop parts of the deposit, on the place, which was incorrectly called like the shaft Pavel by the collectors. In fact, it is system of shafts in places, where came out up to several cm thick lens body of uranium secondary minerals.

Chalcomenite - Zálesí, outcrops.  FOV 2 mm.

Firstly was found the most distinct chalcomenite. Mostly in form of aggregates in quartz veins up to several mm large, very rare were also found perfectly formed crystals in quartz cavities and on its fractures.

Schmiederite was found much more rarer in form of typical heavenly blue needles growing together in several mm large aggregates.

Schmiederite - Zálesí, outcrops.  FOV 3,5 mm.

Molybdomenite formes most often white to transparent needles and rarer tabular crystals.

Molybdomenite- Zálesí, outcrops.  FOV 2,5 mm.

It is necessary to add, that all mentioned minerals were found only extremly rare and it is sometimes necessary to spent more days on the locality to find some better selenium secondary mineral. They can come in association with selenium primary minerals like naumannite, clausthalite and Cu-selenides.

Some other rare selenium secondaries were described, but for some others is necessary to confirm its determination.