Fassaite

Fassaite

Fassaite from Val di Fassa
General
Category Mineral
Formula
(repeating unit)		 Ca(Mg,Fe,Al)(Si,Al)2O6
Identification
Color light-dark green, black
Crystal habit prismatic, short, plane
Crystal system Monoclinic prismatic
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

  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