Fassaite

Fassaite
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) ; H-M symbol: (2/m)
Identification
Color	light-dark green, black
Crystal habit	prismatic, short, plane
Mohs scale hardness	6
Streak	greenish-white
Specific gravity	2.9-3.3

Fassaite is a variety of augite with a very low iron content, Ca(Mg,Fe,Al)(Si,Al)₂O₆.^[1] 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.^[2]

References

^ 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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[Mindat-1] Mindat

[2] 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

[1]

[2]