General Information:
Chemical Formula:
(Mg,Al)8(Al,Si)6O20
Composition:
(Molecular Weight = 683.33 gm)
Magnesium 21.34 % Mg
Aluminum 25.67 % Al
Silicon 6.17 % Si
Oxygen 46.83 % O
Empirical Formula:
Mg6Al6.5Si1.5O20
Environment:
Magmatic and metamorphic rocks.
Locality:
St. Urbain, Charlevoix Co., Quebec, Canada.
Name Origin:
Named after its blue color.
Physical Properties:
Cleavage:
[010] Perfect
Color:
blue, bluish gray, greenish gray, or green.
Density:
3.42 - 3.48, Average = 3.45
Diaphaniety:
Transparent
Habits:
Granular - Generally occurs as anhedral to subhedral crystals in matrix., Tabular - Form dimensions are thin in one direction.,
Hardness:
7.5 - Garnet
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Streak:
white
More details...