Hello,
Remark on Baryte from Pöhla: The locality should be Pöhla Mine (Uranium mine), Luchsbach Valley, Pöhla, Schwarzenberg, Erzgebirge Mts., Saxony, Germany. It has produced some remarkable specimen of golden to honey-coloured (very similiar colours as the golden calcites from Malmberget/Sweden or Ruck's Pit, Florida/USA) up to 10 cm. These xls are always prismatic, the form is similiar to the form of the celestites from madagascar. They usually sit at grey, white to reddish (hematite inclusions) quartz xls (only a few mm typically), often the matrix is druzy or chert-like grey quartz. Fluorite cubes up to a few cm (usually honey yellow like the barytes) have been found in those areas of the veins, too, but I've never seen both minerals at one piece. Double terminated xls are not uncommon.
Good specimen with some undamaged (rare) or little damaged, cm sized xls are often sold for about 50 to 300 Euros, even in Germany.
The geology of the area is quite complex. It mostly consists of upper precambrian to lower cambrian metamorphites (graphite-bearing phyllites, garnet-bearing micashists) with layers of limestones (mostly marbles today). During variscean (or hercynian) orogeny (280-320 million years b.p.) two granite intrusions near the town of Schwarzenberg occurred as part of the widespread intrusions in the Erzgebirge Mts. The first one is synorogenic and strongly deformes (augen gneiss), the second postorogenic. In the area around Schwarzenberg the granite intrusions led to an intense metamorphic overprint on the shists and limestones, forming skarn and calcsilicate rocks, mostly consisting of clinopyroxene (Salite, an intermediate member of the diopside-hedenbergite series), actinolite, garnet (grossularite, andradite), vesuvianite, magnetite and sulphides (mostly sphalerite, chalkopyrite, partly galena, arsenopyrite, löllingite). Some skarns have larger amounts of scheelite (there have been rumors on exploration near Pöhla in 2008).
The mineralogy is quite complex due to complex geology.
In the area of interest, the Uranium mine in Luchsbach Valley, graphite bearing shists (phyllites) are the main hostrock of the veins. But there are also skarns with scheelite and magnetite (the latter being mined as iron ore). Garnet and actinolite are main skarn minerals here. Tin has been mined in the 1970'ies and 80'is in the same mine as the uranium, but other parts of the ore field. The tin ore has been cassiterite. Today the cavities (up to 20x20x40 m, I will look for exact size) are used sometimes for concerts. Parts of the mine are open to visitors (but no collecting underground is possible).
The main interest have been veins of the so-called BiCoNi-Formation (Bismuth-Cobalt-Nickel-Uranium-Silver formation), such as the Schildbach and Kunnersbach vein. Main mineral in the veins has been quartz, accompanied by fluorite and baryte. Siderite has been found, too, as well as hematite. As ore minerals Co-Ni-Arsenides (mostly Skutterudite/Ni-Skutterudite and Safflorite), uraninite, native bismuth and native arsenic, often with proustite, native silver (dentritic up to 20 cm!!), minor argentopyrite.
Regards,
Sebastian Möller
