Archive for the Plagioclase Feldspar Category
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Refractive Index : 1.590 – 1.527
Optical Characteristic : DR, B-, AGG
Specific Gravity : 2.77 – 2.57
Formula : (Na,Ca)(Si,AI)4O8
Crystal System : Triclinic
Variety/Species : Oligoclase/Plagioclase
Species/Group : Feldspar group
Birefringence : 0.007 to 0.010
Dispersion : N/A
Hardness : 6 to 6.5
Toughness : poor
Ultrasonic : Never
Steam : Never
UV Long : Inert
UV Short : Inert
Pleochroism : None
Strength : N/A
Pleochroism Colors : None
Heat [...]
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Refractive Index : 1.568 – 1.599 (+0.005 – 0.005)
Optical Characteristic : DR B +
Specific Gravity : 2.70 (+0.05 – 0.05)
Formula : (Ca,Na)(Si,AI)4O8
Crystal System : Triclinic
Variety/Species : Plagioclase Feldspar
Species/Group : Feldspar Group
Birefringence : 0.007 to 0.010
Dispersion : N/A
Hardness : 6 to 6.5
Toughness : Poor
Ultrasonic : Never
Steam : Never
UV Long : Inert to Weak
UV Short : Inert [...]
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Refractive Index : 1.5590 – 1.568 (+/- 0.05)
Optical Characteristic : DR, Biaxial positive
Specific Gravity : 2.70 (+/- 0.05)
Formula : (Na,Ca)(Si,AI)4O8
Crystal System : Triclinic
Variety/Species : Plagioclase Feldspar
Species/Group : Feldspar Group
Birefringence : 0.007 – 0.010
Dispersion : N/A
Hardness : 6 to 7
Toughness : Poor
Ultrasonic : Never
Steam : Never
UV Long : Inert to Weak
UV Short : Inert to Weak
Pleochroism [...]