Rock Discoveries

Rock Tumbling Grit: Cost-Effective Options and Substitutes

Introduction to Rock Tumbling

Rock tumbling is a great hobby and an exciting way to turn ordinary rocks into shiny and polished gems. However, the cost of rock tumbling can be prohibitive for many due to the cost of rock tumbling grit.

The importance of rock tumbling grit cannot be overstated, as the right grit determines the final result of the rock’s surface. Silicon carbide is the most commonly used rock tumbling grit.

In this article, we will explore the importance of silicon carbide and the difficulty in finding a substitute. We will also discuss the risks and benefits of making homemade tumbling medium and the importance of using consistent grit for avoiding scratches.

Cost-prohibitive Nature

The cost of rock tumbling grit can put a strain on the budget of most hobbyists. Silicon carbide is the most commonly used rock tumbling grit, but it can be relatively costly.

As the quality of the grit increases, so does its cost. However, not all rocks require a high-quality grit.

A beginner can start with a lower quality grit that is more affordable. While it may take longer to get a polished surface, it still produces satisfactory results.

As the hobbyist progresses and begins dealing with larger and harder rocks, a higher quality and more expensive grit may be necessary.

Importance of Rock Tumbling Grit

Rock tumbling grit consists of a series of abrasives that help to grind down the rough surface of rocks. It is available in different grits that range from coarse to fine.

The quality and type of grit used, directly affects the result of the rock surface. Silicon carbide is the most commonly used rock tumbling grit, as it is a hard and durable abrasive.

It does not wear down easily, making it perfect for the tumbling process. It is available in different grades, and its size determines the smoothness of the final surface.

It is important to use the right grit and change it regularly. If left unchanged, the grit may become contaminated with fine rock particles, leading to scratches on the rock surface.

Substitute for Rock Tumbling Grit

The difficulty in finding a substitute for silicon carbide makes it the go-to grit for rock tumbling. Although some materials like aluminum oxide and cerium oxide work, they are expensive and difficult to find.

Limestone and sandstone may also be used, but the results vary, and it takes much longer to achieve a polished surface. Using consistent grit throughout the tumbling process is critical to creating a polished surface.

Inconsistent grit may result in scratches that will be difficult to remove. Therefore, it is best to stick to one type of grit size until the final stages when finer grit is required.

Risks and Benefits of Making Homemade Tumbling Medium

Homemade tumbling medium can be made from materials found at home. Crushed walnut shells, corn cob, and baking soda have been used as alternative tumbling mediums, but they do not produce desirable results.

Making homemade grit from materials such as sandpaper, sandblasting grit, or emery paper has been attempted. However, they may be too abrasive and damage the rocks or cause them to disintegrate.

Additionally, homemade grit may be contaminated with chemicals that may be hazardous to the user.


In conclusion, rock tumbling is an enjoyable and rewarding hobby that requires the use of rock tumbling grit. Silicon carbide is the most commonly used grit, as it is hard, durable, and produces the best results.

While it may be costly, using consistent grit throughout the tumbling process is crucial to avoid scratches and achieve a polished surface. Making homemade tumbling medium is possible, but the results vary, and the risk of using contaminated grit is high.

Materials Used in Rock Tumbling Grit

Rock tumbling grit is composed of different materials that serve as abrasives in the tumbling process. Although there are several types of grit materials, silicon carbide stands out as the best material for rock tumbling.

It is a durable and hard abrasive that breaks down slowly, making it perfect for tumbling hard rocks.

Silicon carbide comes in various grade sizes for the different stages of tumbling.

Course grade silicon carbide works best in the first stage of tumbling, where rough edges are ground down. As the rock surface becomes smoother, medium and fine-grade silicon carbide should be used for finer surfaces.

Ineffectiveness of Sand for Rock Tumbling

Sand is a rough, abrasive material that is ineffective for rock tumbling. It does not break down evenly, and it may contain particles that can scratch or damage rocks.

Sand can also cause other issues, such as clogging the water and drain system in the tumbler. Furthermore, sand is not uniform in shape or hardness, so the tumbling process may not be consistent.

For effective rock tumbling, it is best to use dedicated rock tumbling grit instead of sand. It will provide better results and avoid equipment damage.

First Stage/Rough Grit Substitute

The first stage of tumbling rocks involves grinding down rough edges and shaping them to the desired form. Rough grit is essential for this stage, but substitutes for the rough grit material exist that work just as well.

Instead of using silicon carbide, a cheaper and more accessible alternative is the use of sanding discs. Sanding discs are available in different grit sizes and are easy to find at a hardware store.

They are more economically viable for those on a budget, and they produce the desired effect for the first stage of tumbling.

The Importance of not Overfilling the Tumbler

Tumblers come in different sizes and can accommodate different loads. However, it is important not to overfill the tumbler, especially during the first stage of tumbling.

An overfilled tumbler may cause the rocks to scratch each other or damage the equipment, leading to costly repairs.

Moreover, overfilling the tumbler may cause uneven tumbling due to overcrowding.

The rocks may not be in motion long enough for the rough grit to work effectively on the surface, leading to unsatisfactory results.

It is essential to keep the load within the manufacturer’s recommended limit and to monitor the tumbler regularly to ensure that everything runs smoothly.


In conclusion, silicon carbide is the go-to material for rock tumbling grit. It works effectively, is hard, and durable, and breaks down slowly.

Sand is not an effective material for rock tumbling, and dedicated rock tumbling grit is the best option. For the first stage of tumbling, substitutes such as sandpaper discs may be used.

It is also essential to avoid overfilling the tumbler to achieve satisfactory results. Polishing Stage/Fine Grit Substitute

The polishing stage is the final stage when rock tumbling grit is replaced with a fine grit material to achieve the highest level of shine and smoothness.

While commercial fine grit is available, creating a homemade fine grit substitute can be both cost-effective and convenient.

A homemade mixture of baking soda and water or cerium oxide powder and water can be used as a substitute for fine grit.

The mixture should be thick enough to apply to the rocks and be poured into the tumbler. It should also be well-distributed over the rocks and stirred regularly.

While using a homemade fine grit substitute can be cost-effective, its effectiveness is uncertain. Homemade substitutes may not provide the same consistency and quality of results as commercial grit.

It is best to invest in commercial fine grit substitutes for a guaranteed quality finish.

Rock Tumbling Plastic Pellet Substitute

In the finishing process of rock tumbling, plastic pellets are used to create a cushioning effect on the rocks that prevent chipping. Plastic pellets also provide an added benefit of helping to remove grit residue that can scratch the surface of the rocks.

However, if plastic pellets are unavailable, substitutes can be used. Alternatives like hardwood pellets or corncobs can be utilized.

Hardwood pellets are a great substitute due to their density and hardness, which provides a similar cushioning effect on the rocks. Additionally, they are biodegradable and don’t pose an ecological threat.

Corncobs are another alternative that can be used in place of plastic pellets. They are a softer material and provide a less cushioned effect than plastic pellets, but they still work to agitate the rocks and remove grit residue.

It is essential to note that substitutes for plastic pellets may not be as effective as commercial plastic pellets, and as such, it is best to use dedicated plastic pellets for the final polish stage.


In conclusion, while homemade fine grit substitutes may be cost-effective, their effectiveness is uncertain, and it is best to invest in commercial options for guaranteed results. Though plastic pellets are necessary in the finishing stage of rock tumbling for a polished finish, substitutes like hardwood pellets or corncobs can be used effectively as cushioning alternatives.

However, commercial plastic pellets remain the best choice when it comes to ensuring the best results possible.

Commercial Rock Tumbling Grit Options

When it comes to commercial rock tumbling grit options, a wide range of choices is available. Choosing the right grit can be challenging, especially for beginners.

As such, this article aims to help guide you by recommending the top affordable choices and the best plastic filler pellets for rock tumblers.

Top Choices for Affordable Rock Tumbling Grit

1. Silicon Carbide Grit: Silicon carbide grit comes in different grades, starting from the grittiest (#60/90) to the finest (#1200).

It is cost-effective and the most commonly used rock tumbling grit. 2.

Aluminum Oxide Grit: This grit is a bit more expensive than silicon carbide grit. However, it is still cost-effective and works best in the final stages of polishing and finishing stages of rock tumbling.

3. Cerium Oxide Grit: Cerium oxide is the most expensive of the three mentioned, making it less cost-effective than the other two options.

However, it works exceptionally well for final-stage polishing and is the preferred grit for delicate and soft rocks like opal, turquoise, and jade.

Best Plastic Filler Pellets for Rock Tumblers

1. Polypropylene Pellets: This type of plastic pellet is an excellent choice for rock tumbling, as it is dense and provides a cushioning effect that helps prevent rocks from chipping or breaking.

2. Polycarbonate Pellets: These pellets are a great alternative for those with allergies to polypropylene.

These pellets are more substantial than polypropylene pellets, which makes them a bit more effective at cushioning the rocks. 3.

Acrylic Pellets: Acrylic pellets are the best choice for smaller rock tumblers as they are lighter in weight. However, they are not as effective at providing cushioning and are harder to find.

Conclusion and Call to Action

In conclusion, there are several commercial rock tumbling grit options to choose from. It is essential to choose the right grit for each stage of tumbling and to avoid overfilling the tumbler.

Furthermore, choosing the best plastic filler pellets is essential to achieving the perfect finish. Polypropylene pellets are the most popular choice due to their effectiveness and affordability.

Rock tumbling can be a rewarding hobby, and knowing the right material to use ensures that the results are always satisfactory. Take the time to research and learn more about rock tumbling grit, and share this knowledge with other rockhounds.

Through sharing information and working together, we can foster a community dedicated to the love and appreciation for the natural beauty of rocks. In conclusion, this article has explored the importance of rock tumbling grit and plastic pellets in achieving the desired polished finish for your rocks.

We discussed the cost-effective and top commercial options for grit and the best plastic filler pellets for rock tumblers. We also emphasized the significance of not overfilling the tumbler and the importance of sharing information with other rockhounds to contribute to a community of enthusiasts who value the natural beauty of rocks.


Q: Can sand be used as a grit substitute for rock tumbling? A: Sand is not recommended for rock tumbling as it can scratch or damage rocks and clog the tumbler’s water and drain system.

Q: What are the top affordable commercial rock tumbling grit options? A: Silicon carbide grit, aluminum oxide grit, and cerium oxide grit are all affordable and effective commercial options for rock tumbling.

Q: What are the best plastic filler pellets for rock tumblers? A: Polypropylene pellets are the most popular choice due to their effectiveness and affordability.

Polycarbonate and acrylic pellets are also suitable alternatives.

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