Emerald
green · Beryl family
| Also known as | Beryl (Beryl family) |
|---|---|
| Colour | Green |
| Mohs hardness | 7.5–8 |
| Lustre | Vitreous |
| Streak | White |
| Crystal system | Hexagonal (6/m 2/m 2/m) Space group: P6/mсc |
| Transparency | Transparent to opaque |
| Cleavage | Imperfect on the [0001] |
| Fracture | Conchoidal |
| Chemical formula | Be 3 Al 2 ( SiO 3 ) 6 |
| Specific gravity | Average 2.76 |
What is Emerald?
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium. Beryl has a hardness of 7.5–8 on the Mohs scale. Most emeralds have many inclusions, so their toughness (resistance to breakage) is classified as poor. Emerald is a cyclosilicate. It occurs mainly in association with quartz, muscovite, albite, schorl, microcline, fluorite, smoky quartz and elbaite.
How to identify Emerald
- Lustre: Vitreous.
- Hardness: Mohs 7.5–8 — hard enough to scratch glass.
- Streak: White.
- Habit: Hexagonal (6/m 2/m 2/m) Space group: P6/mсc crystal system.
Emerald in different forms
Stones often confused with Emerald
Frequently asked questions
How hard is Emerald?
Emerald is Mohs 7.5–8 on the hardness scale.
What colour is Emerald?
Emerald is typically green (Bluish green to green).