# Stone tumbling

> A rotary tumbler rounds and polishes stones in stages of ever finer abrasive over weeks; how it is done and which stones suit it.

- Source: https://www.711grados.com/en/stone-tumbling/
- Language: en
- Note: This entry was drafted with the help of AI and is pending review by the author.
- Published: 2026-08-29
- Updated: 2026-08-29
- Translation (es): https://www.711grados.com/es/pulido-de-piedras-en-tambor/
- Author: Sandra Sánchez
- Site: 711 Grados (https://www.711grados.com/)

---

The tumbler spins stones with water and abrasive for days or weeks until they are rounded and polished. It is a simple way to get shiny pebbles.

![Steps of the technique: Load the barrel, Rough, Medium grit, Fine grit, Pre-polish, Polish](https://www.711grados.com/media/diagrams/pulido-piedras-steps.en.svg "Summary of the steps")

## Stages

1. Roughing with coarse silicon carbide (one to two weeks).
2. Medium and fine grit.
3. Pre-polish.
4. Polish with cerium or aluminum oxide. Wash the stones and the barrel between stages.

## Stones

Quartzes, agates, jaspers and stones of similar hardness to each other (≥ 7 on Mohs work best). Do not mix very different hardnesses.

## Result

Rounded, shiny stones, ready to drill and mount as pendants.

## Tips

Fill the barrel to three quarters and do not let it run dry.

## Step by step

1. **Load the barrel.** Stones of similar hardness, up to three quarters.
2. **Rough.** Coarse carbide with water, one to two weeks.
3. **Medium grit.** Clean the stones and repeat.
4. **Fine grit.** Another week.
5. **Pre-polish.** With very fine powder.
6. **Polish.** With cerium or aluminum oxide.

## Tools and materials

- Rotary tumbler
- Silicon carbide of several grits
- Cerium or aluminum oxide
- Filler media (plastic pellets)

## Common mistakes

- Mixing hardnesses: the softer wear away.
- Not cleaning between stages.
- Letting the barrel run dry.
- Overfilling.

## See also

- [Cabochon cutting](https://www.711grados.com/en/cabochon-cutting/)
- [Polishing and buffing metal](https://www.711grados.com/en/polishing-and-buffing-metal/)
- [Quartz and its varieties](https://www.711grados.com/en/quartz/)