Bermanite Locality: Hagendorf South Pegmatite (Cornelia Mine; Hagendorf South Open Cut), Hagendorf , Waidhaus , Vohenstrauß , Oberpfälzer Wald , Upper Palatinate , Bavaria , Germany ( Locality at mindat.org ) Picture width 1 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Bermanite
Bermanite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Mn²⁺Mn³⁺₂(PO₄)₂(OH)₂·4H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1). It is a member of the Arthurite structural group.
Key properties: Mohs hardness 3.5; specific gravity 2.84–2.85; Vitreous to slightly resinous, dull luster; optically biaxial.
IMA symbol Brm, grandfathered status — known before the IMA’s founding, named in 1936.
A late-stage hydrothermal mineral replacing primary phosphate phases, usually triplite or lithiophilite, in complex granite pegmatites.
It is found associated with Triplite, strengite, leucophosphite, huréaulite, lithiophilite, stewartite, sicklerite, rockbridgeite, phosphosiderite, strunzite, switzerite, paulkerrite.
In honor of Dr. Harry Berman (1902–1944), Professor of Mineralogy, Harvard University, Cambridge, Massachusetts, USA.