| Fassaite | |
|---|---|
 Fassaite from Val di Fassa | |
| General | |
| Category | Mineral |
| Formula (repeating unit) | Ca(Mg,Fe,Al)(Si,Al)2O6 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | C2/c (no. 15) |
| Identification | |
| Color | light-dark green, black |
| Crystal habit | prismatic, short, plane |
| Mohs scale hardness | 6 |
| Streak | greenish-white |
| Specific gravity | 2.9-3.3 |
| References | [1] |
Fassaite is a variety of augite with a very low iron content, Ca(Mg,Fe,Al)(Si,Al)2O6.[2] It is named after the Fassa Valley, Italy.
It is thought to be a contact mineral formed at high temperature on the interface between volcanic rocks and limestone. It is also reported in meteorites.[3]
- ^ Dowty, E.; Clark, J.R. (1973). "Crystal structure refinement and optical properties of a Ti3+ fassaite from the Allende Meteorite". American Mineralogist. 58: 230–242. Bibcode:1973AmMin..58..230D. Retrieved 30 December 2020.
- ^ Mindat
- ^ Simon, S. B. and L. Grossman, A comparative study of melilite and fassaite in Types B1 and B2 refractory inclusions, Geochimica et Cosmochimica Acta 70 (2006) 780–798