# Quartz and its varieties

> Quartz is the most common mineral in jewelry (hardness 7): rock crystal, amethyst, citrine, rose quartz, smoky quartz, agate and chalcedony.

- Source: https://www.711grados.com/en/quartz/
- Language: en
- Note: This entry was drafted with the help of AI and is pending review by the author.
- Published: 2026-08-31
- Updated: 2026-08-31
- Translation (es): https://www.711grados.com/es/cuarzo/
- Author: Sandra Sánchez
- Site: 711 Grados (https://www.711grados.com/)

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Quartz is the most abundant mineral in the Earth's crust and one of the most used gems in jewelry. Its varieties cover almost every color and price.

## Properties

- **Composition:** silicon dioxide (SiO₂)
- **Hardness:** 7 on the Mohs scale.
- **Crystalline varieties:** rock crystal (colorless), amethyst (violet), citrine (yellow), smoky quartz (brown) and rose quartz.
- **Microcrystalline varieties:** chalcedony, agate, onyx, carnelian and jasper.
- **Treatments:** many citrines are heated amethysts; the color of some varieties is improved with dyes.

## Uses in jewelry

- Beads, cabochons and faceted stones.
- Affordable rings, pendants and earrings.
- Cameos and hardstone carving.

## Pros and cons

### Advantages

- Affordable and durable.
- A wide range of colors and shapes.
- Widely available.

### Limitations

- It lacks the sparkle of denser stones.
- Some colors are dyed or treated.
- It can be scratched by harder stones.

## Care and cleaning

- Clean with lukewarm water, mild soap and a brush.
- Avoid hard knocks and intense heat.
- For dyed varieties, avoid prolonged water.

## See also

- [Amethyst](https://www.711grados.com/en/amethyst/)
- [Topaz](https://www.711grados.com/en/topaz/)
- [Gemstones in jewelry](https://www.711grados.com/en/gemstones-in-jewelry/)