onyx
Photo courtesy of Scott Papper, GIA GG, AJP, Global Gemology & Appraisals
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Variety: Onyx
Species: Chalcedony Mohs Hardness: 5 to 6 out of 10 Color: Banded variety of chalcedony that has alternating bands of white and various colors such as black, red and green RI: 1.535 to 1.539 (1.53 to 1.54 spot reading) Birefringence: Usually not detectable SR/DR/AGG: AGG Spectrum: Not diagnostic Fluorescence: Generally inert SG: 2.60 (+0.10/-0.05) |
