Alperiste , Slavíkite (File of view: 12 mm) Locality: Prenterwinkelgraben (Bärndorfer Graben), Bärndorf, Rottenmann, Liesing - Palten valley, Styria, Austria Original description: Anhedral grains and aggregates of alpersite (white, with very slight greenish tint; SXRD- and EDS-analysed) on pale yellow-brown crusts of slavikite (PXRD- and EDS-analysed). This specimen is described in Kolitsch, U. (2014): 1992) Alpersit und Slavikit vom Prenterwinkelgraben bei Barndorf, Paltental, Steiermark. P. 137 in Niedermayr, G. et al. (2014): Neue Mineralfunde aus Österreich LXIII. Carinthia II, 204./124., 65-146. — Photo: Harald Schillhammer · CC BY-SA 3.0 de
Slavíkite
A hydrous magnesium-ferric sulfate — a yellow oxidation product of pyrite in Bohemian shales.
Intro adapted from Wikipedia (CC BY-SA).
Slavíkite is an IMA-recognized mineral species in the sulfate class, with the chemical formula (H₃O)₃Mg₆Fe₁₅(SO₄)₂₁(OH)₁₈·98H₂O.
It crystallizes in the hexagonal crystal system (space group R-3).
Key properties: specific gravity 1.91–1.99; Vitreous luster; optically uniaxial.
IMA symbol Sví, IMA status: approved, named in 1926.
An uncommon secondary oxidation product of pyrite in shales and slates.
It is found associated with Halotrichite, pickeringite, fibroferrite, copiapite, melanterite, epsomite, jarosite, gypsum.
In honor of František Slavı́k (1876–1957), Professor of Mineralogy, Charles University, Prague, Czech Republic.