Black crystals of the very rare Sb-Mn oxide mineral filipstadite associated to jacobsite from the famous Langban deposit. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Filipstadite
A very rare manganese-antimony spinel in which ordered cations split both the octahedral and tetrahedral sites.
Intro adapted from Wikipedia (CC BY-SA).
Filipstadite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Fe³⁺₀.₅Sb⁵⁺₀.₅)Mn²⁺₂O₄.
It crystallizes in the cubic crystal system (space group Fd3m). It is a member of the Spinel structural group.
Key properties: specific gravity 4.9; Brown streak; Metallic luster; optically biaxial.
IMA symbol Fps, IMA status: approved, named in 1987.
Found in metamorphosed Fe–Mn orebodies.
It is found associated with Jacobsite, ingersonite, calcite, antimony (Långban, Sweden); hausmannite, forsterite, phlogopite, calcite, copper, hedyphane, svabite (Jakobsberg, Sweden).
The name refers to the town of Filipstad, Sweden, which is near the Långban mine.