General Information:
Chemical Formula:
Al13Si5O20(OH,F)18Cl
Composition:
(Molecular Weight = 1,156.74 gm)
Aluminum 30.32 % Al
Silicon 12.14 % Si
Hydrogen 1.39 % H
Chlorine 3.06 % Cl
Oxygen 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
More details...