Alexandrite
Alexandrite is a colour change variety of chrysoberyl discovered in 1830 in the Ural Mountains of Russia. It was named after the ruling Czar of the time, Alexander II. The colour changes from green in natural daylight to red in incandescent light and candlelight. In good quality stones the colour difference is stunning.
The Ural mountain deposits of Alexandrite have been mined-out and although the gemstone is rare, it is mined in other source locations including, Africa, Brazil, Burma, India, Madagascar, Sri Lanka, Tasmania and USA.
Properties of the Gemstone and Additional Information
| Gemstone type: | A variety of Chrysoberyl |
| Crystal System: | Orthorhombic |
| Chemical Composition: | Beryllium Aluminium Oxide, BeAl2O4 |
| Colour: | Green in sunlight (daylight), red in incandescent light (filament light bulb) and candlelight. |
| Lustre: | Bright vitreous |
| Pleochroism: | Trichroic, strong in dark stones, weak in light stones. |
| Dispersion: | Low |
| Hardness: | 8 1/2 on the Mohs' scale |
| Toughness: | Excellent |
| Cleavage: | Indistinct |
| Density in gm/cc: | 3.71 to3.75 |
| Double refraction: | Yes |
| Refractive index: | 1.74 to 1.76 |
Common Treatments
Alexandrite is not normally treated.