Leonite , Halite Locality: Wintershall Potash Works, Heringen , Werra Valley , North Hesse, Hesse , Germany ( Locality at mindat.org ) From a classic locality also in Germany: leonite as white pseudomorphs after sharp freestanding picromerite crystals to almost 2 cm. They are perched beautifully and 3-dimensionally on matrix of crystallized halite. 5.5 x 4.7 x 3.4 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Leonite
A hydrated potassium-magnesium double sulfate named for Leo Strippelmann, director of the Westeregeln salt works.
Intro adapted from Wikipedia (CC BY-SA).
Leonite is an IMA-recognized mineral species in the sulfate class, with the chemical formula K₂Mg(SO₄)₂·4H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m).
Key properties: Mohs hardness 2.5–3; specific gravity 2.2; Waxy to vitreous luster; optically biaxial.
IMA symbol Leo, grandfathered status — known before the IMA’s founding, named in 1896.
An uncommon secondary mineral of metamorphic origin in marine salt deposits; can occur in volcanic fumaroles.
It is found associated with Kainite, polyhalite, halite, sylvite (New Mexico, USA).
The mineral was named to honor Leo Strippelmann, Director of the salt works at Westeregeln, Germany.