Orschallite Field of view: 1.5 mm Locality: Schellkopf, Brenk, Brohltal, Ahrweiler, Rhineland-Palatinate, Germany ( locality at mindat.org ) . — Photo: Henk Smeets – tomeikminerals.com · CC BY 4.0
Orschallite
Orschallite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Ca₃(S⁴⁺O₃)₂(SO₄)·12H₂O.
It crystallizes in the hexagonal crystal system (space group R-3c).
Key properties: Mohs hardness 4; specific gravity 1.9; Vitreous luster; optically uniaxial.
IMA symbol Ors, IMA status: approved, named in 1990.
A rare species, an intermediate stage in oxidation of sulfides to sulfates, preserved in a melilite nepheline leucitite quenched during a submarine volcanic eruption.
It is found associated with Clinopyroxene, apatite, phillipsite, calcite.
The mineral was named to honor P. Orschall, Cologne, Germany, who discovered the mineral.