Alexandrite
greenredpurple · Chrysoberyl family
| Also known as | Chrysoberyl (Chrysoberyl family) |
|---|---|
| Colour | Green, Red, Purple, Yellow, Blue, Brown |
| Mohs hardness | 8.5 |
| Lustre | Vitreous |
| Streak | White |
| Crystal system | Orthorhombic |
| Cleavage | Distinct on {110}, imperfect on {010}, poor on {001} |
| Fracture | Conchoidal to uneven |
| Chemical formula | BeAl 2 O 4 |
| Specific gravity | 3.5–3.84 |
What is Alexandrite?
The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula Be Al2O4. The name chrysoberyl is derived from the Greek words χρυσός chrysos and βήρυλλος beryllos, meaning "a gold-white spar". Despite the similarity of their names, chrysoberyl and beryl are two completely different gemstones, although they both contain beryllium and aluminium. Chrysoberyl is the third-hardest frequently encountered natural gemstone and lies at 8.5 on the Mohs scale of mineral hardness, between corundum (9) and topaz (8).
How to identify Alexandrite
- Lustre: Vitreous.
- Hardness: Mohs 8.5 — hard enough to scratch glass.
- Streak: White.
- Habit: Orthorhombic crystal system.
Alexandrite in different forms
Stones often confused with Alexandrite
Frequently asked questions
How hard is Alexandrite?
Alexandrite is Mohs 8.5 on the hardness scale.
What colour is Alexandrite?
Alexandrite is typically green, red, purple, yellow, blue, brown (Various shades of green, emerald-green yellow, blue, brownish to greenish black, may be raspberry-red under incandescent).