Information on amethyst
Amethyst is a purple variety of quartz and one of the best-known gemstones and minerals. With a hardness of about 7, amethyst can be suitable for a rock tumbler, but compact pieces work better than fragile crystal points or geodes.
Amethyst is popular for its purple colour, crystal structure and distinctive appearance. The stone is widely used for jewellery, decoration, mineral collections and tumbled stones. When polishing stones, the main question is whether the piece of amethyst is compact enough and does not have too many fragile crystal edges or fracture planes.
What is amethyst?
Amethyst is a crystalline variety of quartz. Like other quartz types, amethyst consists mainly of silicon dioxide. The purple colour is caused by natural traces of iron and by geological conditions during formation. The colour can vary from light lilac to deep dark purple.
The name amethyst comes from Greek and is often linked to old stories about sobriety and protection against drunkenness. Today, amethyst is mainly popular as an ornamental stone, collector’s stone and decorative mineral.
Hardness
Like quartz, amethyst has a hardness of about 7 on the Mohs scale. This means the stone can be suitable for tumbling and polishing.
Colour
The colour ranges from light purple to dark purple. Some pieces have white quartz zones, colour bands or lighter edges.
Is amethyst suitable for a rock tumbler?
Amethyst can be suitable for a rock tumbler, but not every piece of amethyst is equally practical. Compact pieces without fragile crystal points, cavities or deep fractures usually give the best chance of a good result. Beautiful geodes or crystal clusters are often better kept as collector’s pieces.
- Choose compact pieces: massive amethyst is more suitable than open crystal clusters.
- Avoid fragile points: crystal points can break off or become dull in the tumbler.
- Mix with similar hardness: preferably combine amethyst with other quartz-like stones.
- Work from coarse to fine: don’t skip grit stages.
- Use polishing powder: for real shine, fine grit alone is usually not enough.
Practical tip: want to tumble amethyst or other stones? Then also check the category rough stones for rock tumblers.
Polishing amethyst in 5 steps
Polishing amethyst with a rock tumbler usually works best in several stages. A good starting point is four grit stages followed by one polishing stage. The grit stages make the stone smoother. The final stage with polishing powder provides the shine.
Coarse grit
For rounding off rough shapes and sharp edges. Use this stage mainly for compact rough pieces.
Medium grit
For reducing scratches from the coarse stage and making the surface more even.
Fine grit
For further refinement. The stone feels smoother, but usually does not yet have a deep shine.
Very fine grit or pre-polish
For preparation before the final polish. This stage helps to reduce small scratches further.
Polishing powder
For shine. Only use this stage once the amethyst has already become nicely smooth in the previous stages.
Please note: open amethyst geodes, druzy edges and fragile crystal clusters are usually not ideal for the polishing tumbler. They often stay prettier as specimens.
Overview: amethyst and the polishing tumbler
| Property | What does this mean? | For the rock tumbler |
|---|---|---|
| Hardness around 7 | Amethyst is a quartz variety and relatively hard. | Suitable, provided the piece is compact enough. |
| Purple colour | The colour ranges from light lilac to dark purple. | Polishing can bring out the colour and shine more beautifully. |
| Crystal points | Some pieces consist of open crystals or geodes. | Fragile crystals can break off in the tumbler. |
| Compact pieces | Massive rough amethyst is sturdier than open clusters. | Usually the best choice for tumbling. |
Different types of amethyst
Amethyst is sold in different forms. Some names refer to the place of origin, others to colour, pattern or shape. For the rock tumbler, the name is less important than the structure of the piece.
Common amethyst
The familiar purple variety of quartz. Compact pieces can be suitable for tumbling.
Amethyst geode
A cavity with crystals on the inside. Beautiful as decoration, but usually less suitable for the tumbler.
Chevron amethyst
Amethyst with white or grey bands in a V-shaped pattern. Compact pieces can be interesting to polish.
Dark amethyst
Deeper purple amethyst is popular in jewellery and collections. Here too, watch for fracture lines and crystal edges.
Polishing amethyst or other stones?
For a good result, you need suitable stones, a polishing tumbler, grit, polishing powder and plenty of patience. For amethyst, choose compact pieces without fragile crystal points.
Common mistakes when polishing amethyst
Amethyst is hard enough to polish, but fragile forms can still be damaged. Crystal clusters, geodes and pieces with many fracture planes require care.
- Putting geodes in the tumbler: beautiful crystal cavities can be damaged or fill with slurry.
- Using crystal points: points can break off or become blunt.
- Changing grit too quickly: scratches from earlier stages will remain visible.
- Leaving coarse grit behind: this can cause new scratches in later stages.
- Too little fill: stones can knock against each other too hard and become damaged.
- Skipping the polishing stage: without polishing powder, amethyst often stays less shiny.
Can you find amethyst in the Netherlands?
Amethyst is not a common find for hobby collectors in the Netherlands. You may sometimes come across quartz-like stones, small crystals or transported material in gravel, mixed lots or rocks, but you will not easily find beautiful amethyst like that from Brazil or Uruguay here.
If you want to search for stones yourself, also read the page which stones can you find in the Netherlands and Belgium. For a predictable rock tumbler batch, it is usually more practical to buy suitable rough stones.
Buy amethyst or search for it yourself?
Searching for it yourself is fun, but amethyst is not a stone type you can easily find in usable pieces in the Netherlands. Buying rough amethyst is more practical if you want to practise this stone type in a targeted way. In that case, pay particular attention to compact, massive pieces, not just attractive crystal points.
As a collector’s stone
Beautiful crystals, geodes and clusters are often better kept as decorative minerals than put in the tumbler.
For the rock tumbler
Preferably choose compact rough amethyst or a suitable mixed stone blend. For that, see the category rough stones.
Frequently asked questions about amethyst
Is amethyst suitable for a rock tumbler?
Yes, compact pieces of amethyst can be suitable for a rock tumbler. Open crystal clusters, geodes and fragile crystal points are usually less suitable.
How hard is amethyst?
Like quartz, amethyst has a hardness of about 7 on the Mohs scale. This makes the stone relatively hard.
How long does polishing amethyst take?
Polishing amethyst usually takes several weeks. Work step by step from coarse grit to finer grit and then use polishing powder for the shine.
Can you tumble amethyst geodes?
Usually that is not a good idea. Geodes and crystal cavities can be damaged, fill with slurry or lose their sharp crystal structure.
What is the difference between amethyst and quartz?
Amethyst is a purple variety of quartz. Quartz is the broader mineral family; amethyst is one of the best-known colour varieties.