ALEXANDRITE
Alexandrite
Chrysoberyl
Chrysoberyl whose apparent color changes with the light source. The strength of the change differs between stones.
GEM PROFILE
Basic properties
- Mineral or material
- Chrysoberyl
- Main chemical composition
- BeAl₂O₄
- Crystal & structure
- Orthorhombic
The color-change variety of chrysoberyl. Twinning can give some natural crystals an apparently hexagonal form.
- Typical colors
- Green to bluish green in daylight; red to purplish red in incandescent light
- Mohs hardness
- 8.5
A measure of scratch resistance, distinct from resistance to impact or breakage.
About hardness and durability - Representative sources
Examples of known sources. Determining the origin of an individual stone requires examination and comparison with reference material.
- Common cutting styles
- Oval and cushion mixed cuts are common.
Explore cutting styles
LOOK A LITTLE CLOSER
What to observe
Compare the same stone in daylight-like and warm lighting. Pleochroism caused by viewing direction differs from color change caused by the light source.
TREATMENT & CARE
Treatments & care
Treatments & identification
Synthetic alexandrite and other color-changing imitations exist. Color change alone does not prove a stone is natural.
Everyday care
Clean with lukewarm water and mild detergent. Despite its high hardness, protect it from impacts and sudden temperature changes.
Cleaning depends on treatment, inclusions and mounting. If a stone's condition is unknown, ask your jeweler or a gem specialist before cleaning.
READING & REFERENCES
References
Public sources for learning about this gemstone's general properties.
This dictionary provides general educational information. Values are representative and do not identify or grade an individual stone. Locality examples include historical deposits.
Sources checked: October 19, 2026