Antigorite
| Also known as | Serpentine (Serpentine family) |
|---|---|
| Colour | Green, Gray |
| Mohs hardness | 3.5–4 |
| Lustre | Vitreous to greasy |
| Streak | Greenish white |
| Crystal system | Monoclinic |
| Cleavage | (001) Perfect |
| Fracture | Brittle |
| Chemical formula | (Mg, Fe) 3 Si 2 O 5 OH 4 |
| Specific gravity | 2.5–2.6 |
What is Antigorite?
Antigorite is a lamellated, monoclinic mineral in the phyllosilicate serpentine subgroup with the ideal chemical formula of (Mg,Fe2+)3Si2O5(OH)4. It is the high-pressure polymorph of serpentine and is commonly found in metamorphosed serpentinites. Antigorite, and its serpentine polymorphs, play an important role in subduction zone dynamics due to their relative weakness and high weight percent of water (up to 13 weight % H2O). It is named after its type locality, the Geisspfad serpentinite, Valle Antigorio in the border region of Italy/Switzerland and is commonly used as a gemstone in jewelry
How to identify Antigorite
- Lustre: Vitreous to greasy.
- Hardness: Mohs 3.5–4 — soft; a knife will scratch it.
- Streak: Greenish white.
- Habit: Monoclinic crystal system.
Antigorite in different forms
Stones often confused with Antigorite
Frequently asked questions
How hard is Antigorite?
Antigorite is Mohs 3.5–4 on the hardness scale.
What colour is Antigorite?
Antigorite is typically green, gray (Green, yellowish-green, blueish-gray).