obsidian
Species: Obsidian
Mohs Hardness: 5 to 6 out of 10 Color: Dark green or brown to black RI: 1.490 (+0.020/-0.010) Birefringence: None SR/DR/AGG: SR, commonly with ADR Spectrum: Not diagnostic Fluorescence: Generally inert SG: 2.40 (+0.10/-0.07) Routine Treatments: None |