BRANDTITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated arsenates
    Crystal system : Monoclinic
    Chemistry : Ca2(Mn,Mg)(As2O4)2 2H2O
    Rarity : Rare

Brandtite is a rare hydrated arsenate of calcium and manganese, colorless or white, present in hydrothermal manganese deposits. Its name was given to it in honor of the Swedish chemist Georg Brandt. It is a mineral which forms small prismatic crystals up to 8 mm, frequently grouped in radiate aggregates, or spherules and reniform masses with fibroradiated textures.

Main photo : Brandtite from Harstigen Mine, Pajsberg, Sweden © Marko Burkhardt

Brandtite from Fuchs Quarry, Hartkoppe, Bavaria, Germany © Yannick Vessely
Brandtite from Veta Negra Mine, Atacama, Chile © Christophe Boutry
Brandtite from Fuchs Quarry, Hartkoppe, Bavaria, Germany © Carsten Slotta
Brandtite from Fuchs Quarry, Hartkoppe, Bavaria, Germany © Luigi Chiappino

Brandtite in the World

Brandtite occurs in the metamorphic manganese deposits of Sweden (Langban, Harstigen) and New Jersey (Sterling Hill), as well as in the rhodochrosite and rhodonite manganese veins of Schneeberg (Saxony), and Vrancice, near Pribram (Czech Republic).

Brandtite in France

Brandtite has been reported in France at the Salsigne mine (Aude).

Twinning

Common twin on {100}.

Fakes and treatments

No fake inventories for this mineral species.


Hardness : 3.5
Density : 3.67
Fracture : Conchoidal
Trace : White

TP : Translucent to transparent
RI : 1.707 to 1.729
Birefringence : 0.018
Optical character : Biaxial +
Pleochroism : None
Fluorescence : None

Solubility : Acids

Magnetism : None
Radioactivity : None