Royal Ontario Museum Polarised-Light Microscopy Laboratory

Sanidine

(POTASSIC and ALKALI FELDSPARS) Ka[AlSi3O8]

Crystal system: Monoclinic
Refractive index: 1.518-1.534
Birefringence: 0.006-0.007
Cleavage: 1 perfect, 1 good intersecting at right-angles
Twinning: carlsbad
Colour in PPL: colourless
Pleochroism: none
Relief: low
Distinction:
Occurrence: volcanic felsic rocks

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