Zircon
Zircon
High-dispersion zircon in many colors
Blue
Brown
Colorless
Red
Yellow
Optical characteristics
- Ref. index
- 1.81 – 2.024
- Birefringence
- 0 – 0.059
- Luster
- Vitreous to adamantine
- Pleochroism
- Variable Variable depending on transparency, orientation, and variety.
- Fluorescence
- Variable to inert.
Source localities
Myanmar
Myanmar: Mogok Valley
Premium
★ Top Source
Classic source for ruby, sapphire, spinel and other collector gems.
Sri Lanka
Sri Lanka: Ratnapura / Elahera
Premium
★ Top Source
Classic Ceylon source for sapphire and many alluvial gems; known for bright colors and good clarity.
Tanzania
Tanzania: Merelani Hills
Major
Major source for tanzanite, garnet, spinel, tourmaline, ruby and fancy sapphires.
Cambodia
Cambodia: Pailin
Commercial
Historic source for dark blue sapphire and ruby near the Thai border.
Inclusions & features
Crystals Crystal Inclusions
Under 10x loupe: solid, well-formed mineral crystals trapped inside the host gem. They may…
Fractures Feathers and Fractures
Under 10x loupe: irregular internal surfaces that catch light and appear bright, wing-like, or…
Fractures Fingerprint Inclusions
Under 10x loupe: curved or wavy lines of tiny dots forming patterns that look…
Clouds Pinpoint Clouds
Under 10x loupe: concentrations of extremely tiny bright dots that individually are too small…
Crystals Radiation Halos
Under 10x loupe or microscope: a dark brown, gray, or discolored spherical zone surrounding…
Multiphase Two-Phase Inclusions
Under 10x loupe: a transparent irregular cavity containing both a liquid phase and a…
Instruments used
Dichroscope
Reveals pleochroism, instantly eliminates singly-refractive stones
10x Loupe
Your most-used instrument, start every examination here
Polariscope
Determines single vs. double refraction, quick and conclusive
Refractometer
Measures refractive index, the backbone of gem identification
UV Lamp, Long Wave and Short Wave
Fluorescence exposes treatments, synthetics, and origin