Hydrated silica
Opal
- Mohs
- 5.5 – 6.5
- Colour
- Milky base with colour play across the whole spectrum
- Every day
- No
Hydrated silica — not a crystal at all
Opal
Opal holds water — up to a fifth of its weight — and can craze, which is a network of fine cracks that appears when it dries out or gets shocked by temperature. This is not a defect and it is not something a setter can prevent. In a pendant or earrings it will outlive you. In an everyday ring it will not.
The facts
- Family
- Hydrated silica — not a crystal at all
- Hardness
- 5.5 – 6.5 on the Mohs scale
- Colour
- Milky base with colour play across the whole spectrum
- Where hers come from
- Australia, mostly Coober Pedy and Lightning Ridge
- What she pays
- £20 – £300, and the spread is enormous
- Everyday wear
- No
What will damage it
Dry heat, sudden temperature change, and any hard knock. Never leave one on a sunny windowsill and never put it in an ultrasonic cleaner.
In a ring you wear daily
No