How to Cut Rocks

Guidance on the best ways to open rocks, covering every price point – even how to cut rocks for free!

<This article does contain Amazon links but we promise they are helpful!>

Why Cut Rocks Open?

In the world of rockhounding you will often come across rocks which you suspect have something pretty waiting for you on thei nside. They might have a sparkle in the centre, lines under the outer skin, or even eyes - like that stone which looks like the cookie monster.

The famous "Cookie Monster Agate", which is both an agate and a geode.

We cut rocks open to get to the lovely innards and also to produce slices or halves of the same stone. They are easier to polish, the smaller they are. This is also the beginning of the process for shaping rocks into gemstones to be used in jewellery.

Rocks Don’t Always Look Better Cut Open!

A warning before we continue. There are rocks which look better uncut. There are rocks which should never be cut, and there are rocks that become ruined when you cut them.

A great example of this is pyrite. There has been a recent study which showed that fool’s gold – iron pyrite – does actually contain small traces of real gold. As a result, loads of gold panners I know rushed out and smashed up their pyrite pieces.

If they had read to the end of the article/study, they would have seen that the amounts are miniscule… worth far less than the specimen they smashed up.

Cut rocks with caution, particularly if they are precious to you.

You can cut slices of the same rock like this polished slice of mossy agate from Ayrshire.

What are your Options for Opening Rocks Up?

There are loads of different ways in which you can open rocks. Here is the rundown:

·       Use another rock… like a caveman.

·       Using hand tools

·       Using a Dremel

·       Using a Tile Saw

·       Using a Lapidary Blade

·       Using a big ole’ chain

Opening Rocks Safely | Necessary Equipment

Before you rush off and start hammering things like a neanderthal, there are safety precautions which you ought to take, should you try cutting or smashing up rocks.

Make sure you have appropriate eyewear – safety goggles will stop pieces of rock getting into your eyes. We have seen a fragment of rock in someone’s eye before and it is not pretty. Don’t risk it.

You should wear gloves if you are smashing up rocks. The fragments are sharp.

Bring an old towel with you. Wrap anything you want to smash in the towel then smash it. The towel will get wrecked, but your eyes will be safe.

You are likely to need a waterproof apron, preferably in leather, if you are using a saw to cut rocks.

You should always have water on hand when cutting rocks open so that you can avoid breathing in any brick dust.

You should always use a mask when cutting rocks. Not one of those fabric covid masks and not one of the blue medical masks. You want a dustproof mask. You want to make sure you don’t breathe in any brick dust as once it is in your lungs; it stays there forever.

Warnings aside, let’s discuss how to cut rocks by hand to begin with.

How to Cut Rocks by Hand

There are a few different ways to cut rocks by hand. You can use tools, or you can do it on the fly, while you are on the hill, using other rocks.

Some rocks are harder than others. If you are on a hill with no tools and you want to smash a rock open, you just have to find a rock harder than the one you want to smash. Quartz is a hard stone that is abundant. Look for quartz or quartzite to open your rock with.

We do not recommend that you open rocks using rocks, but we do appreciate that sometimes it is the only way. A far better way to cut your rock is by using hand tools.

Big rocks may require a hammer and chisel, as will any rocks which you want to cut a straight line in. You will need both tools plus a mask and goggles. If there is a natural crack in the stone, then follow it. Using a chisel to draw a line where you want to cut and then tapping around that crack sometimes works.

<We found this rockhounding set on amazon which contains a hammer, chisel, gloves, an eye mask, and a whistle. It’s good because it includes a jeweller’s loupe, which is one of those magnifying beasties you see jewellers look at diamonds with>

You will absolutely open 70% of rocks with a hammer if you want to. The cut won’t be neat but sometimes, as in the case of geodes, neatness is not the object. If your rock is harder than quartz, a hammer will struggle. It is time to get the big tools out…

Cutting the rock gives you a flat face to polish. The flatter the surface, the easier a rock is to polish - particularly if you are hand polishing rocks.

How to Cut Rocks Using a Dremel/Rotary Tool

Electroplated diamond coated circular blade. You need to use this on a stone which you keep wet. Score across the stone where you want to cut it and repeat the process until the stone fractures.

Cutting a rock with a Dremel takes a little finesse. Work side on to the stone, running parallel with the ends. Make sure you keep the Dremel to its slowest speed setting.

As with all cutting you need water on hand to keep dipping your rock in. You need safety goggles, and you need a dust mask. When using electric tools like this, use a clean surface that you don’t mind getting messed up. Cutting mats are obviously best.

The Dremel method should only be used on small stones.

Roy’s Rocks have a great short video on YouTube explaining this method really well.

What Type of Tool do You Use to Cut Rocks?

We use the Dremel 3000 but there are cheaper alternatives. The Galaxy Pro rotary tool costs less and has high power settings but comes with a lower star rating. We have not tried it. One Dremel tends to last you for a long time.

For a higher price point, you can buy a rotary tool which is good quality and more powerful. This cordless rotary tool has a higher starting speed of 8,000 RPM. We also like the look of the Dremel 4250. If we were scaling up, we would buy one of these.

How to Cut Rocks Using a Tile Saw

Tile saws will terrify you for the first few uses. After your twentieth cut, though, you are placing your fingers next to the blade to remove rocks. Although we don’t recommend it, you can actually touch the tile saw blade without getting cut. You might still get a sore one, so don’t try that at home.

Tile saws are a good option for cutting rocks open. They don’t have much finesse, but they are a good buy for those who (like us) want to cut rocks on the cheap. They cost around £50-£100 and you can have them delivered to your house.

You should only buy a wet tile saw, so you can cut the rocks using water to eliminate dust. You will also need to spend money on a diamond coated blade that matches the size of your saw. The better the blade, the better the cut.

You can pick up a table saw reasonably cheaply on Amazon, or you can spend extra for more finesse.

This Ayrshire agate was one of the best we have ever sliced. This was cut on a tile saw, hand polished, and then tumbled.

How to Cut Rocks with a Lapidary Blade (Best Option)

Lapidary blades are the best for cutting rocks since that is literally what they are made for. Unfortunately, they are not as cheap as their tile saw alternative. You will still need the diamond coated blade, too.

Lapidary saws usually have compartments or grips where the rocks can be held in a vicelike grip while you cut. Some include lathes. Some have polishing systems built in. They typically take two forms. The cutting saw often used by boys who love power tools, or an adaptation of the tile saw but with additional features which add to the precision of the cut.

This heavy duty cutting saw from Evolution Power tools is big and bold, should you have the space for it.

Expert lapidary blades look like this setup: a 6’’ lapidary saw with a price tag close to a grand. For that you get precision, smooth as butter cuts, and the ideal tool to shape rocks into gemstones worthy of jewellery.

Opening Geodes with a Chain

You can also cut rocks open using a chain. You insert the rock into a loop in the chain, the other ends of which are attached to a motorised tool which tightens the chain’s grip on the rock incrementally until it breaks open.

We don’t use this method but have seen other rockhounds jerry-rig machines to do this. We did find one reference to a tool called a cast iron pipe snap cutter which looks like it would do the same job but by hand. Good luck with that….

Cool Rocks to Cut

To summarise then, you can cut rocks open for reasonably cheap prices, or you can smash rocks open for almost nothing at all. But if you want to make fine cuts for immaculate polishing, a lapidary blade is where it is at.

Keep up the good work!

Katriona cutting rocks in the kitchen. You really ought to use these outdoors. Plus we have since bought her an apron...

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