Best Rock Tumbler Grit

The Best Rock Tumbler Grit (Reviews)

Like it or not, rock tumbling grit is just one of those things we’re going to have to buy to keep enjoying our hobby. When I first started tumbling rocks, I couldn’t believe how fast I went through the packages of grit that came with my Lortone 3A tumbler!

But after I started seeing the results from all those weeks of tumbling…I didn’t care any more.  I just realized it was part of the hobby.  I tried dabbling in making my own tumbling grit, but nothing has ever compared to using the real thing.

So I wanted to share with you what I’ve found to be the best rock tumbling grit, and which also happens to be the best tumbling medium that I use in my own rock tumbler.

The Best Rock Tumbling Grit

1. Polly Plastics Rock Tumbler Tumbling Media

Polly Plastics Rock Tumbler Media has been my go to tumbling grit for a long time now.  I’ve tried using other brands, some of which work just fine, but I continue to come back to Polly Plastics.

All of the bags that contain the tumbling media are resealable, which is especially nice when sharing your rock tumbler with children, as it helps prevent spilling of precious grit!

Polly Plastics Rock Tumbler Grit Kit contains all the material you need for polishing all of your rocks and precious stones. This tumbling grit kit contains:

  • 1 lb. 60 Coarse Silicon Carbide Grit,
  • 1 lb. 180/220 Medium Silicon Carbide Grit
  • ½ lb. 500 Fine Silicone Carbide
  • ½ lb. 1200 Aluminum Oxide Polish
  •  Also included is 1 lb. of  premium plastic pellets for protecting and cushioning fragile stones while tumbling.
  • There’s enough grit in this kit for one use in a 15 lb. tumbler or five 3 lb. tumbles!

2. National Geographic Grit Refill for Rock Tumbler

This is another great kit that provides all the tumbling grit you need to go from rough rocks to polished gemstones. 

And there’s no reason you can’t use this grit even if you don’t have the National Geographic rock tumbler.  This tumbling grit can be used in any kind of rock tumbler that you might have.

Each level of grit in this kit has a unique purpose when tumbled with your rough stones. Grit 1 will round your rocks, giving them the desired shape. Grit 2 will further smooth them once they are shaped. Grit 3 will develop them for the final stage. And Grit 4 will provide the final polish.

What Is Rock Tumbler Grit?

Rock tumbler grit is the stuff we use inside the rock tumbler to bring rocks to a nice smooth finish. Rock tumbler grit is a silicon carbide abrasive that is available in different size granules. These varying sized granules are used for shaping, smoothing and polishing rocks in a rock tumbler. Even though there are different kinds of rock tumbler grit, silicon carbide is the preferred grit for rock tumbling.  This is because silicon carbide has three desirable characteristics:

  • Silicon carbide is hard
  • Silicon carbide can be crushed into sharp, angular particles.
  • Silicon carbide is not expensive.

Rock tumbling is done in four different stages and each consists of a different kind of tumbling medium. These stages start with a very coarse rock tumbler grit and gradually work all the way down to a very fine rock tumbler grit.

Because of this change in different kinds of tumbler medium, it is very important to do a thorough cleaning between stages. 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.


Levels of Rock Tumbler Grit


Shaping (60/90 grit)

Shaping grit is the roughest or most coarse of rock tumbler grit. It is used during the first stage of rock tumbling. This is called the shaping stage.  During this stage you are knocking down all of the rough and sharp edges from the rocks by using a very coarse rock tumbler grit.  This stage reshapes your rocks into more round looking stones.

Medium/Fine Grit (120/220 grit)

This stage of the process will remove any scratches, cracks or dimples that might be visible on the rock. To accomplish this, the grit used is not as coarse as the first stage and is  a bit softer.

Pre-Polish (500 grit)

This stage prepares your rocks for the final polish.  This size rock tumbler grit will completely smooth out your rocks, but will not give the high shine that is often time desirable. For that, you must move on to the polishing stage.

Polishing Grit

After your final barrel cleaning, you’re finally ready for the polishing stage!  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.

You May Also Be Interested In…

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.

We earn a commission if you click this link and make a purchase at no additional cost to you.

If you’re looking for a very high quality rock tumbler, you really want to take a look at the Loratone 3A rock tumbler. I just recently purchased one of these to tumble agates and jasper, and it’s worked just perfectly.

The Lortone 3a has a VERY quiet rubber barrel that has a 3lb holding capacity. And the best thing about the Lortone 3a was just how unbelievably quiet it was.

You can get more information on the Lortone 3A here.


If you’re new to the rock tumbling hobby, or just checking it out, you might find my post, The Best Rock Tumbler For Beginners: Take Your Hobby To The Next Level to be helpful to you on your search.

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