Brown crystals of the rare mineral manganhumite from Kitteln Mine, Nordmark, Filipstad, Värmland County, Sweden. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Manganhumite
Manganhumite is an IMA-recognized mineral species in the silicate class, with the chemical formula Mn²⁺₇(SiO₄)₃(OH)₂.
It crystallizes in the orthorhombic crystal system (space group Pbnm). It is a member of the Humite structural group.
Key properties: Mohs hardness 4; specific gravity 3.83; Subadamantine luster; optically biaxial.
IMA symbol Mnhu, IMA status: approved, named in 1969.
A late-stage skarn mineral formed in recrystallized limestone banded between layers of manganese ore minerals (Brattfors mine, Sweden); in a manganese deposit metamorphosed to the amphibolite facies (Bald Knob, North Carolina, USA).
It is found associated with Katoptrite, magnetite, manganostibite, magnussonite, tephroite, galaxite, manganosite (Brattfors mine, Sweden); sonolite, alleghanyite, rhodonite, kutnohorite.
The name refers to manganese in the composition and relation to humite.