Bermanite - Encyclopedia

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated phosphates
    Crystal System : Monoclinic
    Chemistry : Mn3(PO4)2(OH)2 4H2O
    Rarity : Fairly common

Beraunite is a hydrated iron phosphate of secondary origin which is formed by alteration of primary phosphates, in particular triphylite and lithiophyllite, in granitic pegmatites. Its name was given to it in honor of Harry Berman, professor of mineralogy at Harvard University. It occurs in tabular crystals, often twinned, 5 mm at most, usually grouped in sheaves or rosettes ; also in coatings and lamellar masses. It is a red to dark reddish-brown mineral, darkening on exposure.

Main photo : Bermanite from Jocão claim, Minas Gerais, Brazil © Gianfranco Ciccolini

Bermanite from Hagendorf, Bavaria, Germany © Christian Rewitzer
Bermanite from Sitio do Castelo Mine, Portugal © Pedro Alves
Bermanite from Pedra da Moura Mine, Portugal © Pedro Alves
Bermanite from Collioure, Pyrénées-Orientales, France © Font Philippe

Bermanite in the World

Bermanite is known in fine samples in phosphate pegmatites, notably in those of Hagendorf near Pleystein and Rabenstein, in Bavaria (Germany), but also in Palermo and Fletcher (New Hampshire), Keystone and Custer (South Dakota ) and in Mangualde (Portugal). It exists in the lithiniferous pegmatites of Pala (California) and in that of Sapucaia near Galiléia (Minas Gerais, Brazil).

Bermanite in France

In France, bermanite has been described in pegmatites from the Crozant region (Creuse) and in those from the Collioure region (Pyrénées-Orientales).

Twinning and special crystallizations

Many twins are known : commonly polysynthetic around [101] with {101} as composition plane or around [101] with {101} as composition plane. On {001} around [100], or with 2 or more individuals on {301} around [100] producing composite twins.

Fakes and treatments

No fake or treatment identified for this mineral species.

Hardness : 3.5
Density : 2.85
Fracture : Irregular
Trace : Red to brown

TP : Translucent to transparent
RI : 1.685 to 1.751
Birefringence : 0.063
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None

Solubility : Nitric acid

Magnetism : None
Radioactivity : None