Orange crystal of the rare mineral tegengrenite from Jakobsberg Mine, Nordmark, Filipstad, Värmland County, Sweden. Ex. Erich Laskowski collection (USA). — Photo: David Hospital · CC BY 4.0
Tegengrenite
Tegengrenite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Mn³⁺₀.₅Sb⁵⁺₀.₅)Mg₂O₄.
It crystallizes in the hexagonal crystal system. It is a member of the Spinel structural group.
Key properties: specific gravity 4.58; Sub-adamantine luster.
IMA symbol Teg, IMA status: approved, named in 1999.
Found in a Långban-type Fe-Mn deposit.
It is found associated with Hausmannite, calcite, brucite, dolomite, clinohumite, kinoshitalite, native copper, barytocalcite, bindheimite, cerussite.
The mineral was named to honor Felix Tegengren (1884-1980), Finlandic-Swedish economic geologist.