General Information:
Chemical Formula:
KAl2(Si3Al)O10(OH,F)2
Composition:
(Molecular Weight = 398.31 gm)
Potassium 9.82 % K
Aluminum 20.32 % Al
Silicon 21.15 % Si
Hydrogen 0.51 % H
Oxygen 48.20 % O
Empirical Formula:
KAl3Si3O10(OH)2
Environment:
Granites and pegmatites.
IMA Status:
Approved IMA 1959
Locality:
Common world wide.
Name Origin:
From Muscovy glass, alluding to the Russian province of Muscovy.
Physical Properties:
Cleavage:
[001] Perfect
Color:
white, gray, silver white, brownish white, or greenish white.
Density:
2.77 - 2.88, Average = 2.82
Diaphaniety:
Transparent to translucent
Habits:
Massive - Lamellar - Distinctly foliated fine-grained forms., Foliated - Two dimensional platy forms., Micaceous - Platy texture with "flexible" plates.
Hardness:
2-2.5 - Gypsum-Finger Nail
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
white
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