PYROXMANGITE

    Class : Silicates
    Subclass : Inosilicates
    Crystal system : Triclinic
    Chemistry : MnSiO3
    Rarity : Uncommon

Pyroxmangite belongs to the pyroxenoid family. It is an uncommon manganese silicate, close to rhodonite and which forms a series with the extremely rare pyroxferroite. It is a mineral from manganese deposits transformed by regional metamorphism, more rarely from certain manganiferous metamorphic rocks. Its name is built around the terms pyroxene and manganese, thus evoking the structure and composition of the mineral. Pyroxmangite is pink to purple-pink in color, but is covered with a surface film of red-brown to black-brown oxidation. It commonly occurs in xenomorphic masses, it also forms tabular crystals on {001} measuring up to 10 cm.

Main photo : Pyroxmangite from Taguchi mine, Shitara, Japan © Y. Okazaki

Pyroxmangite from Broken Hill, Australia © Rock Currier
Pyroxmangite from Morro da Mina mine, Minas Gerais, Brazil © Rob Lavinsky
Pyroxmangite from Caspar quarry, Ettringen, Germany © Stephan Wolfsried
Pyroxmangite from Caspar quarry, Ettringen, Germany © Michael Förch

Pyroxmangite in the World

The best deposits of pyroxmangite are in Japan, notably in the Taguchi districts where superb crystals reach 5 cm, and in Australia at Broken Hill, a mine which also produced large crystals. Pyroxmangite is also present in several American sites : Randsburg (California), Boise (Idaho), Galena (Colorado), etc...

Pyroxmangite in France

In France, pyroxmangite forms centimeter-sized pink masses in the mica-schists of Locmaria on the island of Groix (Morbihan). It is also reported in St-Jean-de-Maurienne (Savoie) and Nabias (Hautes-Pyrénées).

Twinning

Lamellar twins are known on {010} and single on {001} but less common.

Fakes and treatments

No fakes listed for this mineral species but very easy to confuse with rhodonite.


Hardness : 5.5 to 6
Density : 3.61 to 3.80
Fracture : Undetermined
Streak : White

TP : Translucent to transparent
RI : 1.728 to 1.758
Birefringence : 0.018
Optical character : Biaxial +
Pleochroism : None
Fluorescence : None

Solubility : Insoluble

Magnetism : NoneRadioactivity : None