General Information:
Chemical Formula:(Mg,Al)8(Al,Si)6O20
Composition:(Molecular Weight = 683.33 gm)Magnesium 21.34 %
MgAluminum 25.67 %
AlSilicon 6.17 %
SiOxygen 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
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