Cummingtonite
ID: 124
Cummingtonite
Chemical Formula
Mg7Si8O22(OH)2
Hardness (Mohs)
5-6
Crystal System
Monoclinic
Streak
White
Luster
Silky, vitreous, dull
Diaphaneity
Translucent to opaque
Color
Grey, greyish-brown, green-brown
Crystal Habit / Mode of Occurrence
Fibrous, columnar, massive
Fun Facts
Cummingtonite is an important rock-forming mineral in many metamorphic rocks.