Pentagonite
Mineral Ca(VO)Si4O10·4H2O
About it
Same chemistry as cavansite but grows as twinned prisms with a five-sided outline and a greener blue; with cavansite near Pune, India, and first found in Oregon.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), cavansite group
- Formula
- Ca(VO)Si4O10·4H2O
- Hardness (Mohs)
- 3–4
- Specific gravity
- 2.33
- Lustre
- vitreous (glassy)
- Crystal system
- Orthorhombic
- Colours
- greenish blue, blue
- Transparency
- transparent, translucent
- Cleavage and fracture
- good in one direction
Typical values: real specimens vary. For more, see mindat.org.