General Information:
Chemical Formula:Al13Si5O20(OH,F)18Cl
Composition:(Molecular Weight = 1,156.74 gm)Aluminum 30.32 %
AlSilicon 12.14 %
SiHydrogen 1.39 %
H Chlorine 3.06 %
ClOxygen 49.79 %
O Fluorine 3.28 %
F Empirical Formula: Al13Si5(O)20(OH)16F2Cl
Environment:Metamorphosed highly aluminous shales
Locality:Postmasburg, South Africa.
Physical Properties: Cleavage:[111] Good
Color:colorless, gray white, pink, or reddish white.
Density:2.88
Diaphaniety:Transparent
Habits:Crystalline - Fine - Occurs as well-formed fine sized crystals., ,
Hardness:7 - Quartz
Luminescence:Non-fluorescent.
Luster:Vitreous (Glassy)
Streak:white
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