Bixbyite - Encyclopedia
Class : Oxides and hydroxides
Subclass : Oxides
Crystal system : Cubic
Chemistry : (Mn, Fe)2O3
Rarity : Uncommon to rare
Bixbyite forms a solid solution with the term Mn2O3. It is a fairly rare mineral that is found in two types of environments : metamorphic manganese deposits, "gondites", and rhyolite lithophyses. It owes its name to the American mineralogist and mineral merchant Maynard Bixby. Bixbyite most commonly forms shiny black masses, as well as small cubic and cubo-octahedral crystals with shiny faces. Under the metallographic microscope, it is characterized by the constant presence of polysynthetic twins organized in square patterns. It is a mineral little known to collectors and which constitutes an accessory ore of manganese.
Bixbyite in the World
Bixbyite in France
In France, bixbyite is reported in Saphoz (Haute-Saône), Gérardmer (Vosges) as well as Maljasset (Alpes-de-Hautes-Provence).
Twinning
The bixbyte commonly twins on {111}. This multiple twin creates crenellated edges (main photo).
The different crystal forms of bixbyite
Fakes and scams
No scam known for this mineral.
Hardness : 6 to 6.5
Density : 4.945
Fracture : Irregular
Trace : Black
TP : Opaque
RI : -
Birefringence : None
Optical character : None
Pleochroism : None
Fluorescence : None
Solubility : Hydrochloric acid
Magnetism : None
Radioactivity : None