Tetrawickmanite Locality: Långban , Filipstad , Värmland , Sweden ( Locality at mindat.org ) Picture width 1 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Tetrawickmanite
Tetrawickmanite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mn²⁺Sn⁴⁺(OH)₆.
It crystallizes in the tetragonal crystal system (space group P4_2/n). It is a member of the Perovskite structural group.
Key properties: optically uniaxial.
IMA symbol Twm, IMA status: approved, named in 1971.
Found as a very rare late-formed mineral in fractures in lithium-rich pegmatite (Foote mine, North Carolina, USA); on a museum specimen from a metamorphosed Fe-Mn orebody (Langban, Sweden).
It is found associated with Bavenite, eakerite, siderite-rhodochrosite, albite, quartz (Foote mine, North Carolina, USA); magnetite, barite (Langban, Sweden).
As the TETRAgonal dimorph of wickmanite.