Demantoid
green · Garnet family
| Also known as | Garnet (Garnet family) |
|---|---|
| Colour | Green |
| Mohs hardness | 6.5–7.0 |
| Lustre | adamantine |
| Streak | White |
| Crystal system | cubic |
| Transparency | Can form with any diaphaneity, translucent is common |
| Cleavage | Indistinct |
| Fracture | conchoidal to uneven |
| Chemical formula | Ca 3 Fe 2 Si 3 O 12 |
| Specific gravity | 3.84 |
What is Demantoid?
Demantoid is the green gemstone variety of the mineral andradite, a member of the garnet group of minerals. Andradite is a calcium- and iron-rich garnet. The chemical formula is Ca3Fe2(SiO4)3 with chromium substitution as the cause of the demantoid green color. Ferric iron is the cause of the yellow in the stone.
How to identify Demantoid
- Lustre: adamantine.
- Hardness: Mohs 6.5–7.0 — about as hard as a steel knife.
- Streak: White.
- Habit: cubic crystal system.
Demantoid in different forms
Stones often confused with Demantoid
Frequently asked questions
How hard is Demantoid?
Demantoid is Mohs 6.5–7.0 on the hardness scale.
What colour is Demantoid?
Demantoid is typically green (light to deep green).