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Chrysoberyl

Alexandrite

Green in daylight to red/purple in incandescent light

Color Change
Optical properties

Optical characteristics

Ref. index
1.741 – 1.76
Birefringence
0.009 – 0.01
Luster
Vitreous
Pleochroism
Strong Variable depending on transparency, orientation, and variety.
Fluorescence
Variable to inert.
Origins

Source localities

Russia Russia: Ural Mountains / Siberia
Legendary ★ Top Source

Classic source for alexandrite, demantoid, diamond and nephrite.

33.3% est. supply
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.

20% est. supply
Tanzania Tanzania: Merelani Hills
Major

Major source for tanzanite, garnet, spinel, tourmaline, ruby and fancy sapphires.

20% est. supply
Brazil Brazil: Minas Gerais / Paraíba / Bahia
Major

Major source for beryl, tourmaline, quartz, topaz, chrysoberyl and rare minerals.

26.7% est. supply
Inclusions

Inclusions & features

Crystals Crystal Inclusions Under 10x loupe: solid, well-formed mineral crystals trapped inside the host gem. They may… Synthetic Curved Growth Striae, Synthetic ID Under 10x loupe in immersion: curved parallel lines flowing through the stone in sweeping… 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… Needles Growth Tubes, Rain Inclusions Under 10x loupe: long thin hollow channels running parallel to each other and to… Clouds Pinpoint Clouds Under 10x loupe: concentrations of extremely tiny bright dots that individually are too small… Multiphase Two-Phase Inclusions Under 10x loupe: a transparent irregular cavity containing both a liquid phase and a…
Identification

Instruments used

Dichroscope Reveals pleochroism, instantly eliminates singly-refractive stones Immersion Microscope See every internal detail clearly, the professional standard 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 Spectroscope Reads characteristic absorption lines, confirms chromium, iron, copper UV Lamp, Long Wave and Short Wave Fluorescence exposes treatments, synthetics, and origin Chelsea Filter Quick chromium test, key for emeralds and rubies