RocksdayAlexandrite vs Emerald
The quickest way to tell Alexandrite from Emerald: Alexandrite feels noticeably heavier for its size (specific gravity 3.7–3.8 vs 2.67–2.78).
The color-change variety of chrysoberyl: green in daylight and red or purple under an incandescent bulb.
Photo: Parent Géry, Public domain
Green beryl colored by chromium or vanadium — one of the four classic precious gems.
Photo: Géry PARENT, CC0
Quick tests
- Heft: Alexandrite feels noticeably heavier for its size (specific gravity 3.7–3.8 vs 2.67–2.78).
Key differences
- Emerald is softer and does not swap green for red.
Side by side
| Property | Alexandrite | Emerald |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 8.5 | 7.5–8 |
| Luster | Vitreous | Vitreous |
| Streak | White | White |
| Colors | Green, Red, Purple | Green |
| Crystal system | Orthorhombic | Hexagonal |
| Specific gravity | 3.7–3.8 | 2.67–2.78 |
| Formula | BeAl₂O₄ | Be₃Al₂Si₆O₁₈ (with Cr/V) |
| Found in | Ural Mountains, Russia; Hematita, Minas Gerais, Brazil | Muzo and Chivor, Colombia; Kafubu, Zambia |
Properties that are the same for both are grayed out.
How to identify alexandrite
- The same stone looks green by a window and reddish under a warm lamp.
- Hardness 8.5 — harder than topaz.
- Ural stones change the most; many newer ones only shift from teal to purple-brown.
Crystal system: Orthorhombic
Full Alexandrite guide →How to identify emerald
- Deep green six-sided prisms with flat ends.
- Almost always has internal fractures and inclusions.
- Hardness 7.5–8.
Crystal system: Hexagonal
Full Emerald guide →More comparisons
Frequently asked questions
What is the difference between alexandrite and emerald?
Alexandrite is a mineral (BeAl₂O₄) with a Mohs hardness of 8.5 and a vitreous luster, usually green, red or purple. Emerald is a mineral with a Mohs hardness of 7.5–8 and a vitreous luster, usually green.
How can you tell alexandrite from emerald?
Alexandrite feels noticeably heavier for its size (specific gravity 3.7–3.8 vs 2.67–2.78). Emerald is softer and does not swap green for red.
Could you tell them apart from a blurry close-up?
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