Bixbyite
Mineral (Mn,Fe)2O3
About it
Shiny black cubes, often with small octahedral corners, in rhyolite cavities with topaz and red beryl. Named for Maynard Bixby; Utah's Thomas Range is the classic place.
- Type
- Mineral
- Group
- Oxide, bixbyite group
- Formula
- (Mn,Fe)2O3
- Hardness (Mohs)
- 6–6.5
- Specific gravity
- 4.9–5.05
- Streak
- black
- Lustre
- metallic, submetallic
- Crystal system
- Isometric (cubic)
- Colours
- black
- Transparency
- opaque
- Cleavage and fracture
- imperfect octahedral; irregular fracture
Typical values: real specimens vary. For more, see mindat.org.