filipstadite

{{infobox mineral | name = Filipstadite | category = Oxide mineral | image = | imagesize = | alt = | caption = | formula = {{chem2|(Mn,Mg)(Sb^{5+}_{0.5}Fe^{3}+_{0.5})O4}} | IMAsymbol = Fps | strunz = 4.BB.05 (10 ed) 4/B.05-70 (8 ed) | dana = 7.2.13.1 | system = Isometric | class = Hexoctahedral (mm) H–M Symbol (4/m 2/m) | symmetry = Fdm | unit cell = a = 25.93 Å (approximated); Z = 216 | color = Black | colour = | habit = modified (pseudo)octahedra | twinning = Poor | cleavage = | fracture = Conchoidal | tenacity = Brittle | mohs = 6-6.5 | luster = Metallic | streak = Brown | diaphaneity = | gravity = | density = 4.9 (calculated) | polish = | opticalprop = Biaxal | refractive = | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | references = }} Filipstadite is a very rare mineral of the spinel group, with the formula {{chem2|(Mn,Mg)(Sb^{5+}_{0.5}Fe^{3}+_{0.5})O4}}. It is isometric, although it was previously thought to be orthorhombic. When compared to a typical spinel, both the octahedral and tetrahedral sites are split due to cation ordering. Filipstadite is chemically close to melanostibite. The mineral comes from Långban, Sweden, a manganese skarn deposit famous for many rare minerals.

==Occurrence and association== In the metamorphic Fe-Mn ore bodies of the Långban-type filipstadite associates with native antimony, calcite, native copper, forsterite, hausmannite, hedyphane, ingersonite, jacobsite, phlogopite, and svabite.