Lahnsteinite
A basic zinc sulfate forming millimetre-scale tabular crystals in goethite cavities at Germany's Friedrichssegen mine.
Intro adapted from Wikipedia (CC BY-SA).
Lahnsteinite is an IMA-recognized mineral species in the sulfate class, with the chemical formula Zn₄(SO₄)(OH)₆·3H₂O.
It crystallizes in the triclinic crystal system (space group P1). It is a member of the Ktenasite structural group.
Key properties: Mohs hardness 1.5; specific gravity 2.98; optically biaxial.
IMA symbol Lah, IMA status: approved, named in 2012.
Found in the oxidized zone of a hydrothermal polymetallic sulfide deposit.
It is found associated with Hydrozincite, pyromorphite, native copper, goethite.
The name refers to the city nearby the locality from which the first specimens were collected.