A cube of Bixbyite with the corners
truncated by the octahedral form {111}.
CHEMISTRY - (Mn,Fe)2O3
CRYSTALLOGRAPHY - Cubic
CRYSTAL GROWTH AND HABITS - Bixbyite normally forms small cubic crystals with minor modifications. It can also be massive.
COLOR AND OPTICAL PROPERTIES - Black, Opaque.
HARDNESS - 6 - 6.5
SPECIFIC GRAVITY - 4.9 - 5.0
LUSTER - Metallic
STREAK - Black
BREAKABILITY - Poor octahedral {111}, fracture is irregular.
OCCURRENCE - Bixbyite is found in gas cavities in rhyolite and in metamorphosed manganese bearing rocks.
ASSOCIATED MINERALS - Topaz, Spessartine, Beryl, Quartz, Sanidine Hematite, Pseudobrookite.
MINERAL NAME - Named after Maynard Bixby who provided the first specimens for testing.