# Opal

> Opal is hydrated silica with a unique play of color; it is soft (5.5-6.5) and sensitive to heat and dehydration, and needs special care.

- Source: https://www.711grados.com/en/opal/
- Language: en
- Note: This entry was drafted with the help of AI and is pending review by the author.
- Published: 2026-09-07
- Updated: 2026-09-07
- Translation (es): https://www.711grados.com/es/opalo/
- Author: Sandra Sánchez
- Site: 711 Grados (https://www.711grados.com/)

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Opal stands out for its play of color: flashes that change with the angle. It is a beautiful, delicate gem that asks for careful handling.

## Properties

- **Composition:** hydrated silica (SiO₂·nH₂O), with between 3 and 21% water.
- **Hardness:** between 5.5 and 6.5 on the Mohs scale.
- **Look:** the play of color comes from silica spheres that diffract light.
- **Origins:** Australia produces most precious opal; also Ethiopia and Mexico.
- **Types:** precious opal, fire opal, doublets and triplets (opal slices on a backing)

## Uses in jewelry

- Rings, pendants and earrings, usually as cabochons.
- October jewelry (birthstone).
- Handmade and designer pieces.

## Pros and cons

### Advantages

- Unique colors: no piece is the same.
- Light.
- Highly prized by collectors.

### Limitations

- It is soft and scratches or cracks.
- It is sensitive to heat, knocks and dehydration.
- Some types are damaged by water (doublets and triplets).

## Care and cleaning

- Clean only with a damp cloth and dry.
- Do not use ultrasonic, steam, hot water or chemicals.
- Avoid heat and prolonged sunlight.

## See also

- [How to clean jewelry with gemstones](https://www.711grados.com/en/how-to-clean-gemstone-jewelry/)
- [Birthstones by month](https://www.711grados.com/en/birthstones-by-month/)