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How To Use A Rock Tumbler (Tips and Techniques!)

how to use a rock tumbler

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Rock Tumblers

Have you ever looked at someone else’s rock collection and wondered how in the heck they got such beautiful looking gemstones?  Believe it or not, you can also make your rocks look just as good!  In this article, I’m going to explain exactly how to use a rock tumbler to elevate your rock collection to the next level!

What Do Rock Tumblers Do?

Rock tumbling, or rock polishing, is an incredibly fun hobby for children and adults alike It gets you outdoors, keeps you active and is a relatively inexpensive hobby to get into.  

In addition, the stones you walk away with at the end of a tumbling session are so beautiful and different than what you started out with. Often times you never would have imagined that dull looking rock could be so beautiful!

The first time I saw a rock tumbler in action was when I was about 9 years old.  Ever since, I have been intrigued by the idea that we can turn ordinary looking stones into beautiful gemstones.

What Is a Rock Tumbler Used For?

A rock tumbler is a fairly simple machine which has the sole purpose of taking ordinary looking rocks, turning them over and over in a mixture of grit (sand) and water and polishing them into smooth, round, brilliant stones.

The tumbling machine has a barrel which is connected to a motor.  The motor is what keeps the barrel constantly moving.

Inside the barrel is where the grit, water and stones are.  As the barrel moves, the grit slowly wears away the sharp edges on the rocks, eventually shaping them and polishing them. This is the exact same process that wears away rocks in nature, just on a much faster track!

Related: 5 Tips on How To Make a Rock Tumbler Quieter

Generally speaking, there are two different types of rock tumblers:

  • Rotary Rock Tumblers
  • Vibratory Rock Tumblers

Rotary Rock Tumblers

Rotary tumblers and vibratory tumblers.  The most common type, especially with beginners to the hobby, are rotary tumblers. These are the ones you may have seen, with the barrel that turns around and around.  Rotary tumblers will not only smooth and polish your rocks, but they also make your rocks round, changing the overall shape of the rock.

The Lortone 3A is a great example of a rotary rock tumbler.  In the picture, you can see the barrel which contains the rocks, is turned over and over by the motor that’s housed in the Lortone Tumbler.

The Lortone 3A is a great rock tumbler for beginners, or anyone else wanting to get into the rock tumbling hobby.

The Lortone 3A is user friendly, incredibly quiet and built to last.

You can learn more about the Lorton 3A Rock Tumbler here.

Recommended!
Lortone 3A Single Barrel Tumbler

This rock tumbler is the same one that I use to polish all of my rocks, and I can't recommend it enough. Compared to other rotary tumblers it's very quiet, which cannot be said for many other tumblers. This one is built to last and is used by professional rock tumblers around the world.

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Single Barrel Rock Tumblers

how to make rock tumbler quieter
Single Barrel Rock Tumbler

Single barrel rock tumblers are exactly what it sounds like. These tumblers have one barrel for tumbling rocks. These are great tumblers for beginners. It’s especially important to remember that with single barrel tumblers that you only mix together rocks of similar hardness.

Use the Moh’s scale of hardness for reference when talking about the hardness of a rock.

Double Barrel Rock Tumblers

Double barrel rock tumblers come with two separate barrels. The benefit of having a double barrel tumbler is that not only can you tumble double the amount of rocks, but you can tumble different batches that are each a different hardness.

Vibratory Rock Tumblers

Vibratory tumblers are a little more advanced, and are generally used to polish rocks that have already been tumbled.  

The advantage of vibratory tumblers is that they are much faster at polishing your rocks than rotary tumblers are.  Many people will even have both kinds of tumblers on hand.  

First they shape their rocks in the rotary tumbler then transition to the vibratory tumbler to smooth and polish.  Doing this can decrease the time it takes to shape and polish your rocks by almost 66%!

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12/06/2022 12:05 am GMT

Chicago Pneumatics 18 lb Vibratory Rock Tumbler is an excellent example of a vibratory rock tumbler. You can see the bowl which sits on top of the machine. You can place your rocks and rock tumbling grit inside the bowl and secure the lid and begin tumbling.

The nice thing about vibratory tumblers is that they are generally faster than rotary tumblers.

You can learn more about the Chicago Pneumatics 18 lb Vibtratory Rock Tumbler here.

What Type of Rocks to Use For Tumbling

Regardless of how excited you might be to get started with your new rock tumbler, you should know that you can’t just throw any old rocks into it and expect to get high quality result.

There are in fact certain characteristics in rocks that you want to look for when choosing rocks for a rock tumbler.

Related: Can All Rocks Be Polished?

What Are Good Rocks For a Tumbler?

The rocks you use should be extremely hard, nonporous, and have a relatively smooth surface. You don’t want to use rocks that have cracks or crevices in them that might be hiding grit. This can wreak havoc on your final product.

Good examples of rocks that are great for tumblers are:

  • Chalcedony
  • Jasper
  • Agate
  • Flint
  • Chert
  • Petrified wood
agate are good rocks for tumbling
Agates are good rocks for tumbling

Rocks NOT To Use In a Tumbler

While there are good rocks to use in a tumbler, at the same time there are certain types of rocks that are not good for tumblers.

You do not want to use rocks that are too soft. Rocks that are too soft will simply be too difficult to polish and is not recommended for beginners. Examples of rocks that are too soft for tumblers are:

  • Soapstone
  • Marble

Where To Find Rocks For Rock Tumblers

Rocks that you can use for your tumbler can be found virtually anywhere. Take a walk around your neighborhood, or a hike through the woods. Always be on the look out for spots that may reveal special kinds of rocks.  These areas might be riverbeds, streams and beaches where erosion has occurred.

Other locations to consider for where to find rocks for tumbling are quarries, construction sites and roadside ditches.

However, if you’re unable to get out to any of these locations, you can always buy rough rocks for your rock tumbler in bulk online.

Where To Find Rocks For Rock Tumblers
Beaches are a great place to find rocks for your rock tumbler

​Buying Rough Rocks In Bulk For Tumblers

If you don’t live in an area where rocks for tumbling aren’t easily accessible, not to worry. You can get your rough or raw rocks for tumbling without ever stepping foot outside!  With the click of a mouse you can have delivered to your doorstep bulk rocks for tumbling.

If looking for a source of high quality rough rocks to use in your rock tumbler, or you just want to know where to buy rocks in bulk,  read my post The Best Rocks For Tumbling (Buy Rocks In Bulk!).

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12/06/2022 12:05 am GMT

The bulk rocks for tumbling from Crystal Allies Materials is the perfect way to order your rocks for tumbling.

These rocks all come crushed to about 1 inch in size, and are ready to start tumbling right away. And there’s at least 12 different kinds of stones in each batch.

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Some of the kinds of raw stones included are Amethyst, Labradorite, Septarian, Rose Quartz, Green Opal, Girasol Opal, Desert Jasper, Blue Apatite, Red Jasper, Petrified Wood, Yellow Jasper and Chrysocolla.

How To Use A Rock Tumbler (Step-By-Step)

Rock tumbling is done in four different stages. Please note, that a thorough cleaning of the barrel is absolutely necessary between each stage.  You want to remove ALL of the grit from the barrel and the rocks before moving on to the next stage.

What You Need

  • Rock Tumbler
  • Rocks
  • Grit
  • Plastic Pellets
  • Water
Rock tumbler barrel filled with rocks and grit

​Stage 1: Shaping (60/90 grit)

The first step in tumbling is to shape with coarse grit.  What this does is knock down all of the rough and sharp edges from the rocks.  This stage also reshapes your rocks into a more round looking stone.

For this stage you want to fill the barrel about half or a little over halfway full of rocks.  Then you’ll add the coarse grit to the barrel.  You want to read the manufacturer’s instructions for your tumbler, but a good rule of thumb is about two tablespoons of coarse grit per pound of rocks.  So be sure to weigh your rocks first!

You can add plastic tumbling pellets to the barrel in this stage if you want, but it is not necessary unless you don’t have enough rocks to fill your barrel.

Finally, fill your barrel with just enough water to cover the rocks. Close the lid.  Attach the barrel and turn your rock tumbler on!

Please note, that if you’ve never used a rock tumbler, they are typically pretty loud.  So think about finding a place in the garage or out in the shop where you can let your tumbler do its thing and not be too disruptive.

In about a week, check on the progress of your rocks.  Are they changing shape?  If so, then it’s time to move onto step 2 of the tumbling process.

Stage 2: Medium/Fine Grit (120/220 grit)

After thoroughly cleaning out all of the coarse grit out of the barrel and rinsing off all of the rocks, repeat the same process as before.  Except this time you will use medium/fine grit and plastic tumbling pellets to help protect the rocks from hitting each other.  This stage of the process will remove any scratches, cracks or dimples that might be visible on the rock.

I tend to keep a closer eye on the rocks during this stage. I like to take a peek at them every other day.

Stage 3: Pre-Polish (500 grit)

After another thorough cleaning, you’re ready for stage 3. Same process as before.  This stage also takes about a week.  Again, I like to keep an eye on things by taking a look every other day or so.

Stage 4: Polishing

After your final barrel cleaning, you’re finally ready for the polishing stage!  If you haven’t used plastic pellets in the previous stages, please use them now.  In this stage you MUST use plastic tumbling pellets to prevent your rocks from hitting against each other and ruining all of the hard work you’ve put in so far.

After a week or so in this stage, your rocks should come out looking brilliant and beautiful.

Stage 5: Burnishing

Most tumbled stones polished in a rock tumbler look pretty good at the end of the polishing step. However, there is one more step that will significantly improve their luster and truly make them shine in some cases.

This fifth and final step is referred to as burnishing. It entails immersing the stones in a heavy soap bath for 30 minutes to an hour.

Place your polished stones in a cleaned out tumbler barrel. Make sure the barrel is about two-thirds full so the stones aren’t tumbling too much against each other.

If you don’t have enough material to fill the barrel or if you need to add cushioning between large rocks, add clean plastic pellets. The burnishing step should be a nice and gentle tumble.

If at all possible, use plastic pellets to cushion the rocks as they’re burnished as opposed to ceramic media.

If you’re using ceramic media, make sure it’s been tumbled. New media frequently has sharp edges that can scratch up your rocks.

A Look Back At The History of Rock Tumblers

Man made rock tumblers, like the kind you and I use, have only been around since the middle of the last century, despite the fact that mother nature has been tumbling rocks for millions of years.

The process of rock tumbling quickly gained popularity. By the 1960s, dozens of companies in the United States were producing tumblers.

If you’ve ever rummaged through an old barn at an estate sale, you might have already noticed that rock tumbler barrels were originally made from paint cans, but have since evolved to use better materials such as rubber and plastic.

While there were dozens of rock tumbler manufacturers at the start of the industry, only two were able to rise to the top and become the best and most well known: Lortone and Thumler’s.

Both of these companies are still in business today providing quality rock tumblers to both rockhound and lapidary professionals.

Aside from professional-grade tumblers, there are a few brands of ‘toy’ tumblers that are ideal for beginners and children. National Geographic and Smithsonian are two of the more well-known brands.

Rock Tumbling Tips

Buy a Quality Rock Tumbler

Don’t waste your money on a tumbler from a craft store or even one from a museum. These are loud and frequently made of low-quality materials that break easily.

They may be adequate for one or two batches of rock tumbling, but after that, you’re out of luck. We recommend that you get one with a rubber barrel to reduce the amount of noise produced.

Also, be sure to get one from a reputable manufacturer. I recommend Lortone tumblers.

Thoroughly Rinse The Barrel After Each Stage

Thoroughly rinse out the barrel after each stage of tumbling. Any remaining grit in the barrel or on your stones will etch or scratch them during the next phase. Your barrel, as well as the stones, must be completely free of grit.

Rock Tumbling Tips
Thoroughly rinse stones and barrel between each stage

Reduce The Noise Level By Covering The Tumbler With a Box

Sometimes we just need that tumbler quieter.

The solution is simple: an easy-to-create soundproofing box reduces noise more than anything else. The problem lies in the construction.

Tumbler motors are inevitably air-cooled, so enclosing them needs to be done carefully. Too much heat will reduce the lifespan of the motor.

To start with, you need a properly sized box. I prefer to base the chamber off of a styrofoam cooler since they already have insulation. With a quieter tumbler, you may even be able to simply get away with just using the cooler with a hole drilled for the cord.

Rock Tumbler Before and After

Before and After of Tumbled Rocks Found in New Mexico

Conclusion

Now that you know how to use a rock tumbler, it’s time to get out there and start collecting rocks to tumble!

Are you new to the rock tumbling hobby?  If so, leave a comment below and tell us how you got into it and what kind of rocks you’re currently tumbling.

Happy tumbling!

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