smoky quartz
Photo courtesy of Scott Papper, GIA GG, AJP, CM (NAJA), Global Gemology & Appraisals
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Variety: Smoky
Species: Quartz Mohs Hardness: 7 out of 10 Color: Predominantly brown RI: 1.544 to 1.553 (very constant) Birefringence: 0.009 SR/DR/AGG: DR to AGG (if highly fractured and semi-translucent Clarity Type: Type I Optic Character: Uniaxial positive. Might show a bull's eye or Airy's spiral optic figure and Brazil law twinning under crossed polarizing filters. Pleochroism: Very weak. Different tones of body color Spectrum: Not diagnostic Fluorescence: Generally inert SG: 2.66 (+0.03 / -0.02) |
