Rock Tumbling 101: A Complete Beginner Guide

If you’re just getting started with rock tumbling, then don’t worry! In this article, you’re going to get the lay out of the land when it comes to rock tumbling, including what a rock tumbler is for, and what rock tumbling is exactly!

So keep reading to find out everything you could want to know about rock tumbling as a beginner!

What Is A Rock Tumbler?

A rock tumbler is a machine designed to smooth and polish rocks, turning them into beautiful, gem-like stones. Think of it as a washing machine for rocks! It’s basically just a barrel that rotates. and as it spins, the rocks inside grind against each other, aided by abrasive grit and water, the rough edges and surfaces of the rocks become polished, leaving you with beautiful gem like stones!

I couldn’t recommend rock tumblers enough. It’s like uncovering a hidden treasure, where a seemingly ordinary rock turns into a beautiful gem. Not only that, it’s also going to teach you patience, and if you keep before and after photos of your projects, you’ll see such an amazing difference!

How Do Rock Tumblers Work?

Rock tumblers are essentially broken down into three parts. The barrel, the motor, and the frame. To understand how they work, you’ll need to know a little bit about each!

The Barrel

The barrel is where all the action happens. It’s where the rocks, water, and grit mix and grind against each other. When you’re looking for a good barrel look for one which minimizes noise, prevents leaks, and of course, is effective at tumbling rocks.

  • Material: The barrel is often made of rubber or heavy-duty plastic. Rubber is a popular choice because it helps dampen the noise generated during the tumbling process.
  • Capacity: Barrels come in various sizes, typically ranging from small 1-pound barrels to larger 12-pound or even 15-pound barrels. The size you choose will depend on the volume of rocks you plan to tumble.
  • Seal: A well-sealed lid is crucial to prevent leaks. Some barrels have screw-on lids, while others might use a metal clamp for sealing.
Closed Rock Tumbler Barrel

The Motor

As you can guess, the motor is what keeps the barrel spinning, so you need to make sure you’re picking a machine with a reliable motor to ensure consistent results and a longer lifespan for your tumbler.

  • Power: Like all motors, they’re going to vary in power depending on what you need them for. A more powerful motor can handle larger barrels and harder rocks but may consume more electricity. However, if you’re just getting started, the standard motor that comes with your rock tumbler will be enough.
  • Speed: Some tumblers come with variable speed settings, allowing you to control the rotation speed of the barrel.
  • Durability: A high-quality motor is designed for long-term use, often running for weeks at a time without overheating.

The Frame

The frame is is what holds your tumbler together, keeping the barrel and motor in place. Normally, this is the part you don’t need to worry about too much as it’s the least likely to break.

  • Material: Frames are usually made from metal or heavy-duty plastic. Metal frames are more durable but may be heavier and more expensive.
  • Design: The frame should be designed to hold the barrel securely while allowing for easy removal for grit changes and rock retrieval.
  • Stability: A good frame will have a stable base to minimize vibrations and noise.
Rock tumbler barrel and frame

How Much Does Rock Tumbling Cost?

Before anything, it’s important to know that how much rock tumbling is going to cost you, relies a lot on how much rock tumbling you plan on doing. While I can give you a rough estimate, the tumbler, grit, and rough you use will all determine the price at the end of the day.

However, here are some rough estimates:

Initial Setup Costs

  • Rock Tumbler: Prices can vary widely, from around $39.99 for beginner models to $300 or more for professional-grade tumblers.
  • Grit Kits: A starter kit can cost between $10 to $30. These usually include different grades of grit for the entire tumbling process.

Ongoing Costs

  • Electricity: Running a rock tumbler for weeks can add to your electricity bill. However, most tumblers are relatively energy-efficient, consuming about the same amount of power as a small light bulb, in fact it may only cost around $8 a month in a lot of the US.
  • Replacement Grit: You’ll need to replenish your grit supply regularly. A bag can cost anywhere from $5 to $25, depending on the grade and quantity.
  • Rocks: If you’re not collecting your own rocks, you might spend around $10 to $20 for a batch of rough rocks suitable for tumbling, however, there’s no upwards limit to the amount you can make.

Optional Expenses

  • Polishing Compounds: Some people like to add a final polish using special compounds, which can cost around $5 to $10 per jar.
  • Accessories: Items like sorting screens or storage containers for your finished gems can add a bit more to your overall expenses, however, these are of course optional!

What Do You Need To Get Started Rock Tumbling?

  1. Rock Tumbler: The cornerstone of your new hobby. Choose one based on your needs, whether you’re a beginner or more advanced.
  2. Rough Rocks: You’ll need some raw material to work with. Look for rocks that are hard and have a somewhat uniform size.
  3. Tumbling Grit: This is the abrasive material that helps smooth and polish the rocks. You’ll need different grades, from coarse to fine.
  4. Water: You’ll add water to the barrel along with the rocks and grit. Tap water works just fine.
  5. Sealable Container: For storing finished rocks or unused grit.

Optional But Helpful

  • Polishing Compounds: These can give your rocks an extra shine in the final stage.
  • Sorting Screens: Useful for separating rocks by size or for rinsing off grit.
  • Safety Gear: Gloves and goggles are good to have when handling rough rocks and abrasive grit.

How To Use A Rock Tumbler: 4 Steps For Beginners

As you can see, there are four main steps to to tumbling rocks, but you may be wondering what each stage is for! Here is why you need to put the rocks through each stage. With each stage, I’ll leave a picture so you can understand what to expect. Here is how my rocks started out:

rocks before tumbling

Stage 1: Coarse Grinding

In this stage, you’re essentially giving the rocks a “rough cut,” to round your rocks out and remove any sharp edges. The coarse grit helps break down the rock’s rough exterior. Without this stage, while the rocks may look more polished at the end of the process, they won’t be near as nice. It really is the foundation of good rock polishing.

At the end of this stage you’ll also notice that the barrel is full of muddy, slushy water. It’s important to remember not to dump this water down the sink as it can damage your pipes. Instead you should rinse your rocks over a bucket to clean them, before disposing of the slurry.

Lastly, once you’ve inspected your rocks, you’ll be ready to move onto stage two! However, be patient. If you think your rocks need more coarse grinding, then run them through stage one again. It’s perfectly normal for one round of grinding not to be enough, another will mostly likely yield better results!

  • Purpose: The primary goal here is to shape the rocks and remove jagged edges.
  • Grit Used: Silicon carbide, usually around 60-90 grit.
  • Duration: Typically 7-10 days.
Rocks After Coarse Grinding

Stage 2: Medium Grinding

In stage 2, you’re going to be refining your rocks EVEN MORE. However, one IMPORTANT thing to remember about this stage is to COMPLETELY remove any grit or grains from the previous stage. It may seem over the top, but, the more thorough you are, the better results you’re going to have.

You’ll also notice during this time, that the barrel isn’t as full as the first stage. To make sure the rocks don’t chip or break, you should also add ceramic media during this stage to make sure it’s at the right level.

  • Purpose: Further smoothing the rocks and preparing them for polishing.
  • Grit Used: Silicon carbide, around 150-220 grit.
  • Duration: Another 7-10 days.

Stage 3: Pre-Polishing

By now, your rocks should be looking pretty good, but they’re not quite ready for the spotlight. This stage is like the final rehearsal before a big performance. You’re ironing out the last few kinks to make sure everything is perfect.

  • Purpose: To remove scratches and minor imperfections.
  • Grit Used: Aluminum oxide, usually 500 grit or so.
  • Duration: About a week.

Stage 4: Polishing

  • Purpose: To give the rocks a shiny, glass-like finish.
  • Polishing Compound: Cerium oxide or tin oxide.
  • Duration: 5-7 days.

What Are The Best Rocks To Tumble?

If you’re just starting out, then here are some of the best rocks to tumble as a beginner! As a general rule, you should try any of the following:

  • Agate
  • Amethyst
  • Aventurine
  • Carnelian
  • Howlite
  • Jasper
  • Moonstone
  • Onyx
  • Quartz
  • Rose Quartz
  • Sodalite
  • Tigers Eye

What To Look For In Rocks To Tumble

When looking for rocks to tumble, you should look at: how hard they are, the size and shape, colors and patterns, how porous they are.

Hardness

First of all, you want to make sure you’re picking the correct hardness for your gems and rocks. When you’re just starting out, I’d recommend the following:

  • Mohs Scale: Aim for rocks that have a hardness of around 7 on the Mohs scale. Quartz is a good example.
  • Uniformity: Try to select rocks that have a similar hardness to ensure even tumbling.

If you’re wondering why hardness matters, it’s because softer rocks can break and fall apart in the tumbler, ruining your batch and wasting your time.

Size and Shape

  • Size: Go for rocks that are between 1 and 2 inches in diameter.
  • Shape: Rounded or semi-rounded shapes are ideal.

Size and shape are crucial because they affect how the rocks interact in the tumbler. Too big, and they won’t tumble well. Too jagged, and they might not polish up nicely. However, if you do want to use jagged rocks, you can repeat the first step of grinding them down a few times.

Color and Patterns

  • Vibrant Colors: Brightly colored rocks like agate or jasper are eye-catching.
  • Patterns: Look for rocks with interesting patterns or banding.

Let’s be honest, we’re all in it for the ‘wow’ factor, right? A rock with vivid colors or unique patterns will look even more stunning once it’s polished.

Porosity

  • Water Test: Drop some water on the rock. If it’s absorbed quickly, the rock is too porous.
  • Visual Inspection: Avoid rocks with visible holes or cracks.

Porous rocks can absorb the tumbling grit, which is a no-go. You want a smooth, non-porous surface for that glossy finish.

Tips For Rock Tumbling

When I first started rock tumbling, I’d peruse the Rock Tumbling Hobby Forum to get ideas and tips on what I should know before getting started! Here are the best tips for rock tumbling I saw!

Tip #1: Always Keep The Barrel 70-75% Full

The first great tip I saw was to always keep the barrel around 3/4’s of the way full. If you find some rocks were ready to polish before others, then move those rocks to the side and continue to polish rough stones, until you have enough stones ready for stage 2.

rock tumbler tip 1 - the first stage is the hardest

Tip #2: A Rock Will Look Similar To How It Looks At Stage 1

This tip is great for me because I’m so impatient. Remember if your rock looks like it should be tumbled more in stage 1, don’t rush yourself, it will only ruin your efforts at the end. Instead put it back in the tumbler and go again.

rocks will look the similar after stage 2

Tip #3: Pick Harder Rocks In The Beginning

If you’re just starting out, then you should pick rocks that are between a 7.0-8.0 on the Mohs scale. This way you’re going to have the best chance of success without them breaking!

when you're starting out pick harder rocks

FAQ

I hope this guide is enough to help you get started rock tumbling for the first time! Here are some frequently asked questions people have about the hobby!

Can You Use Your Rock Tumbler For Other Things?

Absolutely, rock tumblers are versatile machines! Besides polishing rocks, you can also clean rusty metal, polish brass shell and my personal favourite, create sea glass.

However, keep in mind that using your tumbler for different materials may require different types of grit and settings.

What Are Some Good Grit For Your Tumbler?

If you’re just starting out, then typically, you’ll want to use the following grit for each stage of your tumbling journey:

  • Coarse Grit: Silicon Carbide, 60/90 mesh
  • Medium Grit: Silicon Carbide, 150/220 mesh
  • Fine Grit: Aluminum Oxide, 500 mesh
  • Polish: Cerium or Tin Oxide

Where Should You Buy Roughs (Untumbled Rocks)

If you’re just getting started, it’s probably easiest to buy your rock rough from Amazon. However, there are SO many places you can get rough from! Including mineral shows, eBay, and if you plan on tumbling rocks in bulk, you can even get them from suppliers!

What’s The Best Machine For Rock Tumbling?

While the best machine for rock tumbling is always going to depend on what you need it for. If you’re just starting out, I’d recommend the National Geographic Rock Tumbler Kit! It comes with everything you need to get started.

How Can You Find Rocks In Nature To Tumble?

If you want to find rocks in nature, then some of the best places to do so include, riverbeds, beaches, quarries, road cuts, creek beds, and even pay to dig locations!

How Big Should Rocks Be For Tumbling?

This is actually a little more complicated than it seems. There are two parts to the answers.

When it comes to how big rocks should be for tumbling, make sure that no rock is ever bigger than 1/2 the barrel diameter, and always make sure you’re using a mixture of different sized rocks for the best results.

As a rule of thumb, though, I try to keep the rocks I tumble no more than 1-1.5″ in diameter

Recap

There it is! A complete beginners guide on rock tumbling! If you liked this article, make sure you check out the rest of the website! Otherwise, have a great day! And if you have any more questions you can ask them in the comment section!

Leave a Comment