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Sand is the abrasive material present when rocks are naturally tumbled in nature. However, this might not be an advantage when it comes to artificial rock tumbling. Truthfully, have you ever considered using sand for tumbling your rocks?
Rock tumbling with sand is more time-consuming than using silicon carbide grit. Sand is mostly comprised of quartz which has a hardness of 7 on the Mohs scale, the same hardness as most rocks you can tumble. Therefore, sand may only be used to tumble materials that are softer than quartz, or as a pre-grit.
Sand has its benefits if you know when and how to use it, and the best part is, that it’s free. Today, I am going to present to you what kind of rocks you can tumble with sand, detailed costs of using sand in rock tumbling vs carbide grit, and how to make sea glass with sand.
If you are interested in checking out the best tumbling grit you can find them by clicking here (Amazon link).
Sand vs Silicon Carbide Grit
Probably the greatest benefit of sand is that you can get it for free if you are living close to a beach, for example. When you think about it, sand is the natural abrasive material present when rocks are tumbled in nature.
However, things change when it comes to putting sand into a rock tumbler, and here is why:
- Hardness Level
The most commonly tumbled materials, agate, jasper, varieties of quartz, petrified wood, aventurine, or tiger’s eye, all have a Mohs Scale hardness of 7.
Most natural sands are composed of quartz, and this material ranks 7th on the Mohs Hardness Scale as well. But why is this a problem? Well, when two materials have the same hardness levels, they are not very effective at cutting one another.
In comparison, silicon carbide grit has a Mohs hardness level of 9+, and, as such, it is a much more effective abrasive. Sand can be used as an abrasive for tumbling agate or jasper, however, it will take a lot more time.
Additionally, you would need around twice the amount of sand as a substitute grit, than if you would use silicon carbide grit.
If you wish to test a material’s hardness level, simply place it on a glass plate, add a bit of water, then place another piece of glass over and grind the two pieces of glass together. If the material scratches the glass, then it means it has a hardness level of at least 5.
- Shape Matters
Most natural sands have round grains shaped-particles. In comparison, silicon carbide grit particles are angular in shape and because of this angular shape, it is much more effective at producing abrasion that smooths and rounds tumbling rough into polished stones.
Sand might also work, however, it will take more time, and the rocks might end up even sharper or deformed.
- Electricity Cost Efficiency
Though you can get sand for free from the beach or other places, that doesn’t necessarily mean you won’t have to give a penny in another way. You have to remember that the total cost of the tumbling includes electricity.
In most cases, using sand as a substitute would require at least two times more tumbling than when using silicon carbide grit. This inevitably leads to more wear and tear on your machine and ultimately lower quality results.
| Tumbler | kWh per day | kWh per month |
|---|---|---|
| Thumler’s MP-1 | 0.56 | 16.79 |
| Thumler’s A-R1 | 0.99 | 29.62 |
| Thumler’s A-R2 | 0.99 | 29.62 |
| Thumler’s A-R6 | 0.99 | 29.62 |
| Thumler’s A-R12 | 0.99 | 29.62 |
| Thumler’s Model B | 1.30 | 39.12 |
| Thumler’s UV-10 | 1.90 | 57.02 |
| Lot-O-Tumbler Single | 2.59 | 77.77 |
| Lot-O-Tumbler Twin | 2.59 | 77.77 |
However, an exception might be in the case of tumbling very soft materials such as obsidian, marble, fluorite, and calcite. If you find the right type of sand with the proper particle size it might work. Some people use sand to place a frosted finish on tumbled glass or use it as a pre-grit.
Thus, sand can only be used in tumbling processes if it is harder than polished rocks. There are cases where sand works better than silicon carbide grit, but only if you understand where a softer grit produces superior results, like the example below.
TIP: Rock tumblers use various types of grit in the multiple stages of the rock tumbling process to shape, smooth, and polish the stones. Find out the complete guide on tumbling grit in the article below:
Rock Tumbling Grit: Usage, Types, Disposal & Substitutes
Sand Can Be Better
So how can sand be a better alternative grit than silicon carbide? Well, you can make sea glass with sand. Sea glass is often found at the beach as it results from broken glass that was tumbled in the waves of the ocean.
If you want to produce an abraded surface similar to natural sea glass, simply put broken glass in your tumbler and then add sand.
Sand is softer than silicon carbide grit, and thus it cuts the glass very differently. All it takes is a little bit of imagination, and you can do many things with sand.
For example, you can tumble jade with sand. If you find a rock that is a mix of jade and serpentine you can create a jade slick with sand.
Rocks that have a mixture of jade, and serpentine, are found in nature with the softer serpentine mostly worn out, and the harder jade having a dull polish.
If you decide to use sand instead of silicon carbide, the sand will act more aggressively towards the serpentine rather than the jade. The end result will be a beautiful translucent jade slick, something that you cannot achieve with silicon carbide.
You might also use sand as a pre-grit. Sand may also be a better variant when tumbling very soft materials such as obsidian, marble, fluorite, and calcite.
BTW: Do you want to know more about rock and mineral identification? The books listed below are the best ones you can find on the internet (Amazon links):
- Smithsonian Handbooks: Rocks & Minerals
- Gemstone & Crystal Properties (Quick Study Home)
- Ultimate Explorer Field Guide: Rocks and Minerals (National Geographic Kids)
Can you use sand as a pre-grit?
Though it might not be a good idea to use sand to tumble rocks, it might be a good idea to use it as a pre-grit media. You can use sand to partly clean rocks or rocks that have been sitting outside for a while and gathered organic mung.
This tumbling process shouldn’t exceed more than a couple of hours though.
For example, a 4-5Tbsp of sifted beach sand or bulk quartz sand, which is usually available at craft stores, can help you take the sharp edges off of your stones but do not leave it for long as it would round off and break down quickly with most rocks.
Using sand with water, or even just water will do some degree of rounding. However, it is a far cry from what you would achieve from a 60/90 silicon carbide.
Some people use sand in the pre-grind stage before using the first 60/90 stage, to save up on the grit. Thus, it is best to only use sand in the pre-grind stage, at most.
TIP: Do you know the beaches can be full of amazing and beautiful gemstones? Yes, you can find there more than just the sand. Check out which gemstones come from the ocean here:
Which Gemstones Come From The Ocean? Corals, Pearls & more!
FAQs about Tumbling Rocks with Sand
Still did not find the answer to your answers about tumbling rocks with sand? Find frequently asked questions in the section below:
Can you use regular sand in a rock tumbler?
You can use regular sand in a rock tumbler, however, since the sand particles are round grains, it makes them less effective at producing abrasion that smooths and rounds tumbling rough into nice polished stones.
Thus, it will take a lot more time and energy to use regular sand in your rock tumbler, than it would if you would use silicon carbide grit, for example. You should always take into consideration that the softer the grit, the smaller the scratches on your rocks.
Can you use beach sand in a rock tumbler?
Beach sand can be used in a rock tumbler, however, it must be sifted. After the sifting process is complete, beach sand can help you take the sharp edges off of your stones but do not leave it for long. Sifted beach sand is also available in craft stores.
You also should take into consideration what kind of beach sand you are using. For example, black sand is finer than regular sand, yet it has a lot of iron in it. Blasting sand might be a good idea to clean stones, but trying to use it to polish stones wouldn’t work.
Can sand damage or break my rock tumbler?
Using sand to tumble your rocks will eventually lead to wear and tear on your rock tumbler. This is because sand has a Mohs scale hardness of 7, the same as most rocks you can tumble.
Materials of equal hardness levels are not very effective at cutting one another, and thus you have to use your rock tumbler for longer periods of time. This inevitably results in more wear and tear, and eventually, the rock tumbler might break.
Can I use sand and silicone grit together?
It’s not a good idea to use silicon carbide grit and sand together. However, you can use them separately. If you wish to save on your grit, you can use sand only as a pre-grit, after which you can switch to a 60/90.
This way you can save up on your 60/90 grit and make use of the free sand as well. However, be careful of what sand you are using, make sure it is sifted, and don’t leave it for long periods as it can affect the quality of your rocks.
TIP: So you already know how and when is the best time to use sand for tumbling. Using tumbler grit is a better option for rock tumbling but can you reuse tumbler grit? Find out the complete answer in the article below:
Can Rock Tumbler Grit Be Reused? You Should Know This