Bixbyite is a manganese iron oxide mineral. Its chemical formula is: (Mn,Fe)2O3. It is a metallic dark black mineral with a Mohs hardness of 6.0-6.5. It is a somewhat rare mineral sought after by collectors as it typically forms euhedral isometric crystals (such as this one pictured in matrix), exhibiting various cubes, octahedra, and dodecahedra.
Specimen matrix is Rhyolite and also contains tiny Topaz crystals and psuedobrookite needles!
Locality: Wahwah Mountains, Thomas Formation, Utah, USA.Bixbyite was named for the American mineralogist Maynard Bixby (1853–1935), who was responsible for its discovery in 1897. It should not be confused with Bixbite, a red form of beryl.