Tapiolite-(Fe)
Mineral FeTa2O6
Also called Ferrotapiolite
About it
Heavy, black, square-sectioned prisms in granite pegmatites, the tetragonal form of iron tantalate. Hard to tell from tantalite or cassiterite without testing; first described from Tammela, Finland.
- Type
- Mineral
- Group
- Oxide, tapiolite group
- Formula
- FeTa2O6
- Hardness (Mohs)
- 6–6.5
- Specific gravity
- 7.3–8
- Streak
- brown
- Lustre
- submetallic, adamantine (diamond-like)
- Crystal system
- Tetragonal
- Colours
- black, brownish black
- Transparency
- opaque
- Cleavage and fracture
- imperfect; uneven to subconchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.