General Information:
Chemical Formula:
KAlSi3O8
Composition:
(Molecular Weight = 278.33 gm)
Potassium 14.05 % K
Aluminum 9.69 % Al
Silicon 30.27 % Si
Oxygen 45.99 % O
Empirical Formula:
KAlSi3O8
Environment:
Intrusive and extrusive igneous, and metamorphic rocks.
IMA Status:
Approved IMA 1960
Locality:
Common world wide occurrences.
Name Origin:
From the Greek orthos - "right" and kalo -" I cleave" in allusion to the mineral's right angle of good cleavage.
Physical Properties:
Cleavage:
[001] Perfect, [010] Good
Color:
colorless, greenish, grayish yellow, white, or pink.
Density:
2.56
Diaphaniety:
Transparent to translucent
Habits:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Massive - Granular - Common texture observed in granite and other igneous rock., Blocky - Crystal shape tends to be equant (e.g. feldspars).
Hardness:
6 - Orthoclase
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
white
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