- Color: color change, from bluish green (daylight) to purple, red or brown (incandescent light)
- Hardness: 8
- Refractive index: 1.74 - 1.77
- Density: 3.68 - 3.80
- Chemical composition: BeAl2O4
- Crystal structure: orthorhombic
- Origins: Russia, Brazil, Tanzania, Madagascar, Zambia, Sri Lanka, Burma, India.
Alexandrite is a color changing varietal of Chrisoberyl. Stones with a strong color change effect are more valuable and represent the most expensive gemstones. Alexandrites are generally not treated.