monoclinic
Orthoclase
KAlSi3O8
Quick Facts
Hardness
6-6.5
Specific Gravity
2.55-2.63
Refractive Index
1.518-1.526
Crystal Structure
monoclinic[2/m]:{010}@1.0 + {001}@0.8 + {100}@0.9 + {110}@0.6 monoclinic
2/m
{010} {001} {100} {110}
Physical Properties
Crystal Systemmonoclinic
Hardness (Mohs)6-6.5
Specific Gravity2.55-2.63
CleavagePerfect {001} and {010} at approximately 90 degrees
FractureUneven to conchoidal
LustreVitreous to pearly
Optical Properties
Refractive Index1.518-1.526
Birefringence0.005-0.008
PleochroismNone to weak
Dispersion0.012
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Open in Playground monoclinic[2/m]:{010}@1.0 + {001}@0.8 + {100}@0.9 + {110}@0.6 Related Minerals
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