Would you like to know how to open a geode? The common ways are smashing it, using a crack hammer and rock chisel, a lapidary saw, or a soil pipe cutter.
Each method has its pros and cons as we will see. What you choose depends on what suits your needs, the tools you have, or what you are trying to achieve.
Do you need a clean cut, or do you just want to see what is inside? Is the geode to be cut into halves or not? Would you polish it afterwards or not?
For instance, if you want a clean half-cut geode, smashing it may not work as it will result in many small pieces.
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Important: Safety first
Before you crack open your geode, you need to ensure you and the people around you are safe.
Also, an adult should supervise children and teenagers during every geode opening activity.
Wear safety goggles, gloves, and a mask if the method you use process will emit dust. Also, people around should have safety wear.
Note: If a mask is necessary, ensure it is at least N95 or higher. Breathing silica dust predisposes someone to silicosis especially to people who often cut rocks as a job or hobby.
Things to note about opening geodes
Geodes are hollow or partially filled subrounded structures lined with mineral masses or crystals. Similar structures that are filled are thundereggs that occur in rhyolitic lava flows, ash deposits, or tuff.
They rattle when you shake them and are lighter than rocks of comparable size since they have voids as their center.
Secondly, geodes vary in hardness, and the thickness of the rind and lining mineral masses or crystals vary. The lighter has more void. This can have an impact on how easily they break or open.
Lastly, always use the right tools designed to cut stone. While some you can modify, the right tool will do a better job.
Ways on how to open a geode
Let us look at the four common ways to open a geode. We will give you the tools you need, how to go about it, pros and cons.
Note: In all the ways of breaking geodes, you need to have your goggles and gloves on. People watching also need protection if close.
1. Breaking geodes with a crack hammer or a bigger rock
This process involves hitting the geode with a larger rock or a geologist/crack hammer. The tools you need are a larger rock or crack hammer. However, a towel or a sock will make the process safer.
To crack open a geode, place it on a firm surface like a wood board or a study surface and hit it with the larger rock or crack hammer.
It will shatter, breaking the geode into many small pieces, some of which will fly away and cause injuries.
You can make it safer by wrapping the geode inside a towel or putting it in a sock before you strike it. They will prevent small chips from causing injury.
The use of a sock or towel is good for children or adults wary or rock chip injuries. It is also good when people are present as it will avoid injuries.
Warning: Don't place your geode on a concrete floor, tile, or kitchen counter, as the crack hammer can break, chip, or damage these surfaces.
Pros
It is quick, easy, and inexpensive. Also, you can use it even on very large geodes.
Cons
It breaks the geode into many small pieces, some with sharp edges. Therefore, you will not get clean halves, making the results messy or less spectacular.
Additionally, this method is likely to damage or ruin the interior of the geode, and unless wrapped with a towel or sock, it can cause injuries.
2. Using a rock chisel and hammer to open a geode
The use of a rock chisel and hammer is a common way to split geodes. Find a flat, hard, stable surface. Also, a pry bar will prove handy, and to prevent movement, secure your geode with a clamp or carpenter’s vise.
Then, place your flat rock chisel on the geode’s surface and tap it with your rock hammer to create a score. Do this with the right force to ensure the chisel only creates a score without shattering your geode.
Continue scoring a line along the circumference until you have a complete circle. Repeat to make the scored line deeper. This creates a line of weakness that promotes a clean break.
Afterwards, create a small crack along the score that you created by increasing the force you apply with your rock hammer. Next, use a pry bar to try to push apart or separate the geode. It will break along the place where you created your score lines.
Once separated, inspect it for any sharp edges and smoothen any as it can cause cuts.
Pro tip: Don't use a screwdriver, wood chisel, or ice pick. Also, ensure you use a flat chisel, not an appointed one, for creating holes.
Pros
It produces a relatively clean cut, splitting the geode into two nearly equal half pieces. Also, you can use this method even on geodes with very large diameters.
Cons
It is time-consuming. Also, applying the wrong amount of force on the rock chisel with your crack hammer will make it shatter.
3. Using a mason or lapidary saw to cut geodes
The other way to open a geode is by using mechanical or powered rock or lapidary saws. A saw with a carbide or best diamond tip will give a clean cut, splitting your geode into halves or as you desire.
Besides the saw, you need a clamp to secure it firmly. Furthermore, water and a small spray bottle or pump sprayer to sprinkle water on the blade to keep it cool during the cutting process is necessary
Start by securing your geode, then cut it with your saw. During this process, some should sprinkle water continuously on the blade to help keep it cool. If alone, use a trickling hose.
If using a powered rock saw, most automatically cool the blade as it cuts using water or other coolants. Take care not to cut yourself.
Warning: This method is suited for only adults Also, while people recommend the use of a tile saw or a grinder, we don't recommend their use because they will not give a clean cut that minimally messes minerals inside the geode.
Pros:
If you use a lapidary saw, it will create a clean, polished cut with minimal damage to mineral masses or crystals inside the geode. You can keep one piece and sell the other.
Also, the process is relatively neat as it doesn’t produce a rabble pile.
Cons:
Rock or lapidary saws are costly. Not everyone can afford to buy them. However, you can rent to minimize on cost. Also, they damage crystals inside the rock as they cut through them.
The other disadvantage is the fluid used may damage delicate minerals. Additionally, the slurry formed can spatter around. However, some lapidary saws have a protection to prevent spattering.
4. Use a soil pipe cutter
Using the soil pipe cutter, i.e., the wheeler type, is the best way to cut a geode. This method is what you will typically see vendors or show people use.
You have a choice of a manual or a powered soil pipe cutter. This cutter has sharp, carbide-tipped roller blades that do the cutting.
This method is
To use a soil pipe cutter, wrap its chain around the circumference of your geode. Then, secure the chain on the correct notch before pressing the lever handle.
The chain with sharp blades will squeeze and cut open the geode by splitting it into halves.
Warning: During the cutting process, it can send pieces flying as the geode breaks. Therefore, adult supervision is necessary for children or teens.
Pros:
The soil pipe cutter creates a neat cut while protecting the delicate crystals inside geodes.
Also, it is quick, cleaner, and easier compared to scoring with a hammer and rock chisel.
Cons:
The soil pipe cutter is costly unless you buy second-hand ones, which are cheaper.
Most have a limited diameter they can cut. One that caught larger diameters exists, but they are expensive.
Lastly, some can send flying tiny fragments that can cause injury.
Consider professional help to open a geode.
If you don’t want to deal with the hassle of opening a geode or you don’t have the right tools, you should consider hiring a professional. They have the right tools and expertise to precisely cut your geode as you desire.