Global Gemology - Rare Gems & Jewels
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REFRACTIVE INDEX

Picture
A refractometer is a tool gemologists use to measure a gem's double refraction, known as its birefringence.
Photo courtesy of Scott Papper, GIA GG, AJP, CMA (NAJA), Global Gemology & Appraisals

A gem's refractive index is the single most important piece of information in a gemologist's quest to identify a gem.

R.I. = Velocity of Light in Air ÷ Velocity of Light in a Gemstone

Click Here to view the Refractive Index Chart.
  • HOME
  • ABOUT
  • SHOP
  • SERVICES
    • APPRAISALS
    • EXPERT WITNESS TESTIMONY
    • SELL YOUR JEWELRY
  • GEMOLOGY
    • GEM ENCYCLOPEDIA
    • THE ART OF GEMOLOGY
  • JEWELRY EDUCATION
    • DIAMOND FACTS
    • JEWELER DIRECTORY
    • JEWELRY PERIODS
    • POCKET WATCHES
    • NATIVE AMERICAN JEWELRY
  • GLOSSARY