identified this stone yet
Alexandrite (Natural)
| Hardness | 8.5 |
| Specific gravity | 3.68-3.78 |
| Refractive index | 1.741-1.760 |
| Crystal system | 斜方晶系（クリソベリル） |
Daylight: blue-green to forest green. Incandescent (or candlelight): raspberry red to purplish red. Russian Ural material shows the strongest, cleanest change; Brazilian and Sri Lankan stones often shift to a softer brownish red.
- nclusions
- Needles and silk
- nclusions
- nclusions (rutile, apatite)
- Doubly refractive, biaxial positive
- Strong trichroism: green, orange, red
- 01Sharp, complete color change between daylight and incandescent is the headline test
- 02Three-color through a dichroscope distinguishes alexandrite from color-change garnet and synthetic corundum imitations
- 03Curved bands or unusually clean material suggests Czochralski synthetic
- 04Flux synthetics may show wispy veils and platinum platelets
- Durable for daily wear
- Safe to ultrasonic and steam unless heavily fractured
- Worth photographing under both daylight and tungsten — color shift is the identity
From $2,000/ct for commercial material with weak change up to $100,000+/ct for fine Russian Ural stones with strong change and clean clarity.
Note: Color change strength is the dominant value driver — over 60% change is considered fine. Carat-for-carat, fine alexandrite over 3 ct exceeds top ruby and sapphire prices. Synthetic alexandrite (Czochralski and flux) is common; verify with a lab report.
Alexandrite is chrysoberyl (BeAl₂O₄) trace-doped with chromium, which sits in a crystal field where green and red transmission are nearly balanced — small shifts in light source produce a dramatic color change. Mohs 8.5 with no makes it surprisingly tough for an extremely rare collector stone.
Origins
Discovered in 1830 in the Ural Mountains of Russia. Ural material remains the benchmark and is essentially mined out. Brazil's Hematita mine produced excellent material in the late 1980s. Sri Lanka, Tanzania (Tunduru), and India contribute most of today's supply, though fine color-change material remains exceptionally rare.
History
Discovered on April 29, 1834 — the day of the future Tsar Alexander II's coming of age — and named in his honor. The green and red echoed the colors of Imperial Russia, and the stone became a symbol of the empire. Modern lapidaries call top alexandrite 'emerald by day, ruby by night.'
Lore & symbolism
June's birthstone (modern, alongside pearl and moonstone). Said to bring luck and balance, and to strengthen intuition. The 55th wedding anniversary gem.
Tools to confirm this stone
Tools that help confirm Alexandrite (Natural). Tap any item to jump to the matching section on the gem tools page.
- 10× loupeDETAILS →
Essential 10× tool to read inclusions, polish marks, and color zoning
- High-output penlightDETAILS →
Switch between daylight and warm incandescent light to verify color change
- DichroscopeDETAILS →
Strong pleochroism — confirm both axes through twin windows
- Chelsea filterDETAILS →
Quick chrome-content screen — chromium-bearing stones glow red through the filter
- Handheld spectroscopeDETAILS →
Absorption-line pattern identifies the chromophore (Cr, Fe, or Co)
- Last reviewed
- April 28, 2026
- Bibliography
- Gem Encyclopedia / GIA (Gemological Institute of America)
- Gem Identification Standards / Central Gem Laboratory (CGL), Tokyo
- Mineral & Gem Database / Mindat.org / Gemdat.org
- Introduction to Gemology / Gemmological Association of All Japan (GAAJ)
The gemological data on this page (refractive index, specific gravity, hardness, crystal system, etc.) is cross-checked against the authoritative primary sources listed above. Values may be revised as gemological research advances.