Magnesioferrite - Encyclopedia
Class : Oxides and hydroxides
Subclass : Oxides
Crystal system : Cubic
Chemistry : MgFe2O4
Rarity : Uncommon
Magnesioferrite is essentially the spinel of volcanoes. It forms a continuous series with magnetite. Although this spinel is also known in many sometimes more original contexts (burning coal mines, maerls subjected to high temperature combustion of coal seams, kimberlites, carbonatites, metamorphic dolomites, etc...), it is essentially a mineral which crystallizes in fumarolic deposits. Its name derives from its chemical composition : magnesium + iron. Magnesioferrite rarely occurs in octahedral crystals of 5 mm at most, more often in irregular grains or aggregates, brownish black in color.
Main photo : Alluvial maghemite from the Carapooee gold mine, Victoria, Australia © Judy Rowe
Magnesioferrite in the World
Twinning
Twins are common on {111}.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 5.5 to 6.5
Density : 4.56 to 4.65
Fracture : Irregular
Streak : Dark red
TP : Opaque
RI : -
Birefringence : 0
Optical character : None
Pleochroism : None
Fluorescence : None
Solubility : Hydrochloric acid
Magnetism : FerromagneticRadioactivity : None