Dioptase
| Colour | Green, Blue |
|---|---|
| Mohs hardness | 5 |
| Lustre | Vitreous |
| Streak | Green |
| Crystal system | Trigonal |
| Transparency | Transparent to translucent |
| Cleavage | Perfect in three directions |
| Fracture | Conchoidal |
| Specific gravity | 3.28–3.35 |
What is Dioptase?
Dioptase is an intense emerald-green to bluish-green mineral that is cyclosilicate of copper. It is transparent to translucent. Its luster is vitreous to sub-adamantine. Its formula is Cu6Si6O18·6H2O, also reported as CuSiO2(OH)2. It has a Mohs hardness of 5, the same as tooth enamel. Its specific gravity is 3.28–3.35, and it has two perfect and one very good cleavage directions. Additionally, dioptase is very fragile, and specimens must be handled with great care. It is a trigonal mineral, forming six-sided crystals that are terminated by rhombohedra.
How to identify Dioptase
- Lustre: Vitreous.
- Hardness: Mohs 5 — soft; a knife will scratch it.
- Streak: Green.
- Habit: Trigonal crystal system.
Dioptase in different forms
Stones often confused with Dioptase
Frequently asked questions
How hard is Dioptase?
Dioptase is Mohs 5 on the hardness scale.
What colour is Dioptase?
Dioptase is typically green, blue (Dark teal, emerald green).