Maghemite - Encyclopedia
Class : Oxides and hydroxides
Subclass : Oxides
Crystal system : Cubic
Chemistry : Fe2O3
Rarity : Quite common
This iron oxide, dimorphic from hematite, forms at low temperature in the oxidized surface zones of metal deposits. Maghemite comes from the oxidation of magnetite at low temperature or more rarely from the dehydration of lepidocrocite ; there is also a series of intermediate terms with magnetite of which it has the crystalline structure and strong magnetism. Its name is composed of the words magnetite and hematite, emphasizing the latter characteristic. Maghemite is a relatively common mineral constituting brown-black grainy to powdery masses, without clear crystals expressed (except in exceptional cases). It is an iron ore exploited at the same time as magnetite.
Main photo : Alluvial maghemite from the Carapooee gold mine, Victoria, Australia © Judy Rowe
Maghemite in the World
Twinning
No twin known for this mineral species, but can replace magnetite octahedra (pseudomorph).
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 6
Density : 4
Fracture : Undetermined
Streak : Brown
TP : Opaque
RI : -
Birefringence : 0
Optical character : None
Pleochroism : None
Fluorescence : None
Solubility : -
Magnetism : FerromagneticRadioactivity : None