Hannebachite Locality: Hannebacher Ley (Hannebacher Lay), Hannebach, Niederzissen, Eifel Mts, Rhineland-Palatinate, Germany Original description: tabular colorless crystals of hannebachite up to 2.06 mm — Photo: Matteo Chinellato · CC BY-SA 3.0
Hannebachite
Hannebachite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Ca(SO₃)·0.5H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbna).
Key properties: Mohs hardness 3.5; specific gravity 2.52; White streak; Vitreous luster; optically biaxial.
IMA symbol Hbc, IMA status: approved, named in 1983.
Lining cavities in blocks of melilite-nepheline-leucitite at the base of a volcano.
It is found associated with Calcite, aragonite, gypsum, barite, celestine, thaumasite, chabazite, phillipsite, gismondine, whewellite, perovskite.
The name is derived from the locality, Hannebacher Ley volcano, Germany, from which the first specimens were collected.