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It’s no secret that rock tumbling is a process that demands a great deal of patience, as it can take several days for your specimens to finally emerge from the tumbler, ready to shine in all their glory. Most rocks suitable for tumbling have a Mohs scale hardness of around 7, including favorites like jade (6.5-7), agate (7), jasper (7), chalcedony (7), petrified wood (7), and quartz (7). Feldspars, with a hardness of 6-6.5, also make excellent tumbling candidates. On the softer side, lapis lazuli (5-5.5) and obsidian (5-5.5) tend to shape more quickly in the tumbler due to their lower hardness. So, just how long does it take to tumble rocks to perfection?
The harder the material, the longer it will take to tumble. And since most rocks you can tumble are quite hard, it may take more than a week to see your stones again. However, if you want to discover the different values of various rocks, read on, as I have prepared a special treat for you!
Today, I will show you exactly how long it takes to tumble various rocks. I will show you what influences the duration of rock tumbling. There are several factors, so activate your rock tumblers as you read this, and let’s begin!
If you want to check out the best rock tumblers, you can find them here (Amazon link).
What Elements Affect the Duration of Your Rock Tumbling?
For one reason or another, everything beautiful and enjoyable takes time. No matter how you look at it, time plays an important part in appreciating something. Would you be as satisfied if you could tumble your rocks in a few minutes?
Probably yes, probably no, but there are some things you should know about rock tumbling, such as the fact that the type of rock tumbler you are using, the type of stones, and the grit, among other things, dictate your time investment.
For example, it takes between 4 to 8 weeks to tumble your rocks with a rotary tumbler, while with a vibratory tumbler, it may take you between 1 and 2 weeks. And here is why:
Rotary Tumblers
Rotary tumblers are probably the most common type of rock tumblers, and they sure do test an enthusiast’s patience since they are slower than vibratory tumblers, with the process usually taking 4 to 8 weeks until completion. But hey, we want to sort out the wannabes; just kidding!
Rotary tumblers are great since they build enthusiasm and involve several processes before you finish, making you feel like a scientist, creating something extraordinary and beautiful.
When it comes to rotary tumblers, there is a four-step process involved: the coarse grind, medium grind, fine grind (known as the pre-polish step), and the polishing stage.
Every stage usually takes one week, which is why rotary tumbling is mostly associated with four weeks, but this isn’t always so.
For example, some enthusiasts prefer super-shaped rocks and may run the coarse grit stage for two, three, or even four weeks.
If you inspect your rocks and wish to improve them, you will tumble them for over a week in the other three stages.
As you can see, how long it takes to tumble your stones with a rotary tumble depends on your preferences, but the minimum time is four weeks regardless.
Using a rotary tumbler is quite simple: you seal your rocks in a soft rubber barrel, together with a grinding compound known as “tumbling grit” (you can also use sand, by the way; here is how), and add a little water.
The barrel will roll on the tumbling machine for several days, and thus, the rocks tumble inside the barrel. Now it’s time to talk about the faster type of rock tumbler, the vibratory tumbler.
By the way, if you are looking for a rotary tumbler, I recommend buying this tumbler on Amazon with the best value for the money you can get.
TIP: Check out the article below if you want to know more about how rotary rock tumblers work and how to choose the best one for your needs:
Rotary Rock Tumblers: How They Work & Which One Is Best?
Vibratory Tumblers
The vibratory tumblers are usually twice as fast as rotary tumblers. Tumbling your rocks with a vibratory tumbler may take up to two weeks.
Vibratory tumblers are relatively simple devices, as they possess a bowl rapidly shaken by a motor. This shaking effect produces a lot of friction between your specimens. Because of this, much unnecessary material is removed from your rocks.
You will often see these devices run from 12 to 24 hours straight! And they will require a medium grit. After this process, the used grit and mud are washed from the rocks.
This stage is repeated for up to seven days until the rocks are nicely smoothed. Depending on your rock specimens and their starting conditions, it can take only three days.
These rocks are then processed for two to three days in fine grit, known as pre-polish, and then two or three days with polish.
Thus, the process of tumbling rocks with vibratory tumbles takes between 1 and 2 weeks. It all depends on what stones you are using and the results you seek.
With that being said, why do people still choose rotary tumblers? It all has to do with the fact that vibratory tumblers are twice as expensive and that the grinding step of a vibratory tumbler “smoothes” the rock but doesn’t “round” it in the same way that a rotary tumbler would.
Perhaps, in the end, it’s just a matter of preference, with those who prefer rounded rocks choosing rotary tumblers and those who prefer angular stones using vibratory tumblers.
I personally recommend using this vibratory tumbler here (Amazon link).
TIP: Check out the article below if you want to know more about how vibratory rock tumblers work and how to choose the best one for your needs:
Vibratory Rock Tumblers: How They Work & Which One Is Best?
Using Both Vibratory and Rotary Tumblers
You can use a rotary tumbler and a vibratory tumbler to tumble-polish rocks. This way, you can also finish tumbling your rocks much faster.
To use this technique, you have to start with the rotary tumbler. Leave your specimens in the tumbler for up to three weeks with a coarse grit, ensuring that your samples are rounded.
Now you are done with the rotary tumbler, which will follow the usual three-step process with your vibratory tumbler. This will produce rounded rocks two weeks faster than you would obtain with a rotary tumbler alone.
Rock Type – Influences
What type of rocks you are using will always dictate the time it will take to have them tumbled. For example, softer rocks such as calcite, marble, Obsidian, or fluorite will always shape more quickly in a rock tumbler than harder rocks.
This is because they have a Mohs hardness of 3 (calcite and marble, 4 (fluorite), and 5.5 (Obsidian), respectively. When it comes to harder stones such as jasper (7), agate (7), petrified wood (7), or varieties of quartz (7), their Mohs hardness is far more significant, and thus it will take several days more to shape and polish.
You should choose your rocks carefully and ensure they are of relatively equal size and hardness (usually the same specimens) since only one unsuitable stone can negatively affect the rest of your batch.
- Hardness
The best rocks for tumbling are hard, having a Mohs scale hardness between 2 and 5. If your specimens are too soft, they won’t polish well; if they are too hard, the abrasives cut them too slowly.
- Density
Regarding density, tumbling rocks shouldn’t have pore spaces or fractures. These spaces can trap particles of grit, hindering the polishing process.
These fractures can also lead to rocks breaking inside your rock tumbler, while the sharp edges might scratch your other specimens inside the tumbler.
- Smoothness
Rocks suitable for tumbling should generally have a smooth surface and shouldn’t be gritty or grainy. This makes them much more comfortable to polish.
Rocks with grit or particles that get released when you rub them together will inevitably scratch the other specimens inside your tumbler, and this is something you want to avoid.
- Size
Regarding the size of the rocks you use in a rock tumbler, one thing to consider is that your largest specimen shouldn’t be more than half a barrel’s diameter.
Since rock tumblers vary in size, so will the size of your rocks. For example, you should use a mixture of stones between 0.25″ and 1.25″ in a 3lb capacity barrel.
When it comes to larger tumblers, they should also be filled with smaller pieces of rocks; however, the maximum size of your biggest specimen can be slightly larger, up to 2″ in diameter, or only half the diameter of your barrel.
Never load your barrel with only large rocks, as this will be less efficient, with little to no grinding taking place. This is why smaller particles are also used; they remove loose material, filling the gaps between the larger stones.
This process favors the particle-to-particle contact, and thus, it will increase the efficiency of your rock tumbler. If your specimens are of equal sizes, you should use a ceramic pellet as a filler, as it will increase the amount of grinding. Let’s look at the different values of various rocks and see how long it will take to tumble them.
TIP: Larger rocks are usually too big to tumble so that the solution can be cut into smaller pieces. Check out this step-by-step guide on how to cut rocks with a hammer and chisel:
Step-by-Step: How to Cut Rocks with Hammer and Chisel
Values for Rock Tumbling – Different Types of Rocks, Minerals, Crystals
Remember, anything below a Mohs hardness scale of 7 can be considered a soft material, and it usually takes less time to tumble.
Specimens with a Mohs scale of 7 or more are much harder, and the tumbling process takes more. Now let’s see how long it takes to tumble various rocks, minerals, and crystals:
Calcite
Calcite rocks come in different colors, from green, red, and pink to dark blue, black, and so on. They have a Mohs scale hardness of 3; thus, it is a soft rock unsuitable for tumbling.
However, if you decide to tumble this beautiful stone, it would take around two to three days to complete the tumbling process.
Marble
Marble, like calcite, has a Mohs scale hardness of 3. It can be tumbled in a vibratory, rotary tumbler, or even worked by hand, and it comes in various colors.
The marble will tumble very quickly; you should use it with equally soft materials. If you decide to work it by hand, it will take a long time; however, marble will be finished in two to three days in a rock tumbler.
Fluorite
Fluorite is also a soft material, having a Mohs scale hardness of 4. It takes around four to five days for fluorite to round nicely in a rotary tumbler and about 48+ hours in a vibratory tumbler to bring them to a polishing stage.
When tumbling fluorite, remember to add ceramic media, and you will also need 1000 Grit Aluminum Oxide, 500 Grit Aluminum Oxide, and dry corn cob.
Obsidian or Apache Tears
Obsidian or Apache Tears usually take around seven days or more to tumble in a rotary tumble, at least. When it comes to a vibratory tumble, Obsidian / Apache Tears will tumble much quickly in approximately two to four days.
This is because Obsidian has a Mohs scale hardness of 5 to 5.5, the same as Apache Tears. Because these materials have a similar hardness, they can be tumbled together.
Lapis Lazuli
The beautiful blue-colored Lapis Lazuli is a beautiful rock, and when it comes to its hardness (5 to 5.5), it is the blue equivalent of black Obsidian or Apache Tears stones.
Lapis Lazuli is a more sensitive rock; you shouldn’t tumble it for 15-30 minutes. If the stone fades, then it means you had a fake Lapis Lazuli or the specimen was dyed/treated lapis cab.
TIP: Lapis lazuli is one of the oldest gemstones known. That’s why there are dozens of fakes that evolved since antiquity. Find out more in the article below:
Real vs. Fake Lapis Lazuli: Focus on These 6 Differences
Feldspars
Feldspar stones such as amazonite, moonstone, labradorite, and sunstone are popular for rock tumbling, each having a Mohs scale hardness between 6 and 6.5.
These stones are challenging to tumble since they can easily break if they get roughly tossed in the tumbler. Tumble feldspars stones will take around 6 to 7 days, but don’t forget to check them regularly.
Jade
Now, we are entering the hard rock zone, and Jade certainly is one, having a Mohs scale hardness of 6.5 to 7. When tumbling Jade stones, you can expect around four weeks of hard work, at least in a rotary tumbler.
In a vibratory tumbler, Jade stones will be finished in around one or two weeks or so. It all depends on the results you want from these beautiful stones.
Jasper
Jasper is a very commonly tumbled stone, and you will need coarse, medium, and fine grit, and then you will undergo the polishing process.
Each of these steps requires one week of tumbling; thus, it will take a month to tumble Jasper since it has a Mohs scale hardness of 7.
You can tumble Jasper for two weeks in the coarse grit step for more excellent results; thus, expect to tumble Jasper from 4 to 5 weeks.
Agate
Agate, like Jasper, has a Mohs scale hardness of 7. It is a beautifully multi-colored stone, which, like its previously mentioned cousin, may take up to five weeks to tumble in a rotary tumbler.
If you want to hasten the process, though you will get slightly different results (rotary = round – vibratory = angular), you might choose a vibratory tumbler and finish tumbling your specimens almost twice as fast.
Petrified Wood
How long does it take to tumble petrified wood? The same is true for Agate and Jasper: between 4 to 5 weeks, or twice as fast with a rotary tumbler since it has a Mohs scale hardness of 7.
This means one or two weeks in coarse grit, one week in medium grit, one week in fine grit, and one week is reserved for the polishing step. But the results are worth it! And petrified wood is quite beautiful.
TIP: Many petrified wood is unsuitable for rock tumbling or lapidary work because it has too many faults and fractures. Check out how to cut and polish petrified wood in the article below:
How To Cut & Polish Petrified Wood: Follow These 3 Steps
Chalcedony
Chalcedony is quite a hard rock, even though it has a Mohs scale hardness of 7, the same as Jade, Agate, Jasper, or Petrified Wood; it will take you around seven weeks of tumbling to get the best results for this type of rock.
This means it takes more than 2 or 3 weeks to tumble than the other materials, which have a similar Mohs scale hardness. But the results are worth it nonetheless!
Quartz
All varieties of Quartz have a Mohs scale hardness of 7. It can take between 5 to 7 weeks to tumble Quartz, and this is because certain types of Quartz are harder to tumble than others.
For example, quartz crystals, solid quartz, or pebbles are easy to tumble; however, water-worn quartz is much more difficult than crystalline quartz since it can pit and undercut depending on how stable it is.
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)
FAQ about Tumbling Rocks
Still, have you not found the answer to your questions about tumbling rocks? Find frequently asked questions in the section below:
What Kind of Rocks Can You Put in a Rock Tumbler?
Regarding rock tumbling, you generally want to tumble rocks with a Mohs scale hardness of around 7. Soft rocks such as calcite (3), marble (3), fluorite (4), Obsidian (5-5.5), Apache Tears (5-5.5), Lapis Lazuli (5-5.5), or feldspars (6-6.5), are suitable for tumbling, but you have to check them regularly.
More challenging specimens such as Jade (6.5-7), Jasper (7), Agate (7), Petrified Wood (7), or varieties of Quartz (7), such as amethyst, tiger’s eye, citrine, aventurine, carnelian, or types of Feldspars (6-6.5), are excellent for rock tumbling, but they require more tumbling time.
What Happens When You Tumble Rocks?
When you tumble rocks, you basically do what Mother Nature has done for thousands of years. You are knocking off the edges and shapes and smoothing out rough rocks.
When you use a rotary rock tumbler, you are rounding the rocks, but when you use a vibratory rock tumbler, you make those stones more angular.
How Long Does it Take to Make Sea Glass in a Rock Tumbler?
You can make sea glass using a rock tumbler in around six days. After you’ve tumbled the glass for three days, you can open the barrel and check its status.
Leave it for 48 more hours, after which you can decide to leave it more or not based on its appearance. Note that the longer you tumble sea glass, the older it will appear.
TIP: Many DIY sea glass tutorials online allege you can make sea glass by shaking broken glass, water, and sand together in a mason jar. This is unrealistic, at best. Find out the complete guide in the article below:
Step-by-Step: Making Sea Glass With & Without Rock Tumbler