Brandtite - Encyclopedia
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 in the World
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