Vonsenite
Mineral Fe2Fe(BO3)O2
About it
Heavy black needles and granular masses, the iron-rich partner of ludwigite, in skarns. First found near Riverside, California; named for collector Magnus Vonsen.
- Type
- Mineral
- Group
- Borate, ludwigite group
- Formula
- Fe2Fe(BO3)O2
- Hardness (Mohs)
- 5
- Specific gravity
- 4.2–4.3
- Streak
- black
- Lustre
- submetallic, metallic
- Crystal system
- Orthorhombic
- Colours
- black, greenish black
- Transparency
- opaque
- Cleavage and fracture
- none
Typical values: real specimens vary. For more, see mindat.org.