Global Gemology - Rare Gems & Jewels
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obsidian


Vintage Mexican alpaca & volcanic sheen obsidian carved Aztec warrior pendant
Photo courtesy of Scott Papper, GIA GG, AJP, CM (NAJA), Global Gemology & Appraisals
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

obsidian facts

Vintage sterling silver & volcanic obsidian glass bracelet
Photo courtesy of Scott Papper, GIA GG, AJP, CM (NAJA), Global Gemology & Appraisals


Obsidian is a natural glass formed by the rapid cooling of volcanic lava.

Obsidian is hard yet brittle, chipping easily, leaving sharp edges.  In ancient times, obsidian was sharpened into blades and arrowheads.

Sheen obsidian has either a golden or silver aventurescent sheen.
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  • HOME
  • ABOUT US
  • SHOP
  • GEMOLOGY
    • GEM ENCYCLOPEDIA
    • DECORATIVE PRINTS
    • THE ART OF GEMOLOGY
  • APPRAISALS
    • INSURANCE
    • DIVORCE
    • ESTATE TAX
    • ESTATE DISTRIBUTION
    • CHARITABLE DONATION
    • LIQUIDATION
    • APPRAISALS THRU EMAIL
  • SELL YOUR JEWELRY
  • JEWELRY EDUCATION
    • DIAMOND FACTS
    • JEWELER DIRECTORY
    • JEWELRY PERIODS
    • POCKET WATCHES
    • NATIVE AMERICAN JEWELRY
  • GLOSSARY