Kunzite is the light pink to violetish purple variety of the mineral spodumene. It is named after the gemologist George Frederick Kunz.
Properties
| Refractive index | 1.660 to 1.676 |
|---|---|
| Birefringence | 0.014 to 0.016 |
| Optic character | Doubly refractive (biaxial) |
| Dispersion | 0.017 |
| Specific gravity | 3.18 |
| Hardness (Mohs) | 6.5 to 7.0 |
| Crystal system | Monoclinic |
| Pleochroism | Strong: colorless, pink, violet |
| Absorption spectrum | Not diagnostic for kunzite |
Published values. They change a little from stone to stone. Our tools do not model kunzite yet. Sources: GIA · International Gem Society
In more detail
It is pleochroic, with the best color seen down the length of the crystal, so cutters orient it with care. Kunzite may be irradiated and then heated to improve its color. Both natural and treated color can fade with heat and bright light. It has perfect cleavage in two directions, so protect it from hard blows and avoid steam or ultrasonic cleaners.
Related terms
- Pleochroism: Pleochroism is the property of a colored doubly refractive stone to show different colors in different directions. It happens because the stone absorbs its rays differently.
- Cleavage: Cleavage is a mineral's tendency to split along flat planes in its crystal structure. A hard knock in a cleavage direction can split a stone.
- Irradiation: Irradiation is exposing a gem to artificial radiation to change its color. Heating sometimes follows, to modify the color further.
- Heat treatment: Heat treatment is controlled heating of a gem to change its color or clarity.
- Stability: Stability is a gem's resistance to damage from heat, light and chemicals.
- Morganite: Morganite is the pink variety of the mineral beryl. Traces of manganese cause its color.