Fassaite
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.
| 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] |
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]
References
- 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
- Schumann, Walter (1991). Mineralien aus aller Welt. BLV Bestimmungsbuch (2 ed.). p. 223. ISBN 3-405-14003-X.
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