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Refractive Index


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, CM (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 US
  • SHOP
  • GEMOLOGY
    • GEM ENCYCLOPEDIA
    • REFRACTIVE INDEX CHART
    • BIRTHSTONE CHART
    • 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