Wer kennt Voltzin ?

[giantcrystal]

Hallo aus Mittelfranken

durch die mineralogische Literatur geistert seit Jahrzehnten ein Zinksulfid namens Voltzin von zweifelhaften Status. Mal ist die Rede von einem Zink - Arsen - Sulfid, mal die Rede von einer Mischung von ZnS mit einer metallorganischen Verbindung, gelegentlich auch von einem Zink - Oxysulfid so ähnlich wie Kermesit...

Weiß jemand Näheres oder kennt eine gute Beschreibung dieses anscheinend in durchaus größeren Aggregaten vorkommenden Minerales ?

Danke und Glück Auf

Thomas

[alfredo]

Hello Thomas,

I bought a piece of "voltzite" from Nevada, and all I could find in it was jarosite.

cheers,
Alfredo

[berthold]

Hallo,

zur Geschichte der Irrungen und Wirrungen zu Voltzin liefert die google-Büchersuche  reichlich Fundstellen. Nach neueren Untersuchungen waren es immer Fehlbestimmungen, entweder Mineralgemenge oder Sphalerit / Wurtzit.

FRANTIŠEK VESELOVSKÝ,  PETR ONDRUŠ, JAN HLOUŠEK (1997) History of secondary minerals discovered in Jáchymov (Joachimsthal), Journal of the Czech Geological Society, 42/4, 115-122

Voltzin was described from Jáchymov by Vogl [60]. It forms hemispheric aggregates and botryoidal stalactitic coating. It is straw yellow, brown red or greenish white in colour, translucent, with a greasy to vitreous lustre. It has a conchiodal fracture. Density 3.5 to 3.8 g.cm-3, hardness 3.5. The mineral is often coated by pyrite. The chemical analysis done by J. Lindacker in Abertamy. Repeated analyses gave Zn 69.08, S 27.47, Total 96.55 wt. %. After recalculation to ZnS, 13.80 wt. % Zn remain. Calculation of this amount of Zn to ZnO requires 3.45 wt. % ogygen, i.e., the same amount which is miss-ing to 100 % of the analysis. The mineral was found in the Geister vein, Eliáš mine, at the level of the Barbora adit, 270 m below surface. This section shows an upgraded mineralization, including argentite, proustite, native silver and bismuth, galena, sphalerite, black secondary minerals of Ag, pyrite and native arsenic. Voltzin occured in drusy cavities in the upper part of the vein deposited in porphyry. The present restudy of specimens Nos. NM 12913 and NM 12914 from the collection of the National Museum in Prague proved that sphalerite of a poor crystallinity is the only crystalline phase.

Gruß
Berthold