Opening a geode is like opening a birthday present – you don't know what's inside until you break into it. There are many techniques for cutting a geode open and pros and cons to each method. Whether you choose a low-tech approach or use a specialized tool for the task, there is one piece of equipment that is essential for the project: safety goggles. No matter how you open a geode, there is the possibility of creating rock splinters or shards, so protecting your eyes is the first step of the process.
Always wear safety goggles when trying to open a geode. An adult should supervise children and teens trying to open geodes.
Simple and Economical Methods
Opening a geode can be as simple as smashing it with a larger rock or throwing it against a boulder. To prevent pieces from flying all over when you break the geode open, put it inside of a sock or wrap it with a towel. The advantage of this method is its simplicity, but the disadvantage is that it is messy. Cracking a geode like this will work, but you may end up with many fragments instead of a clean cut.
Using a hammer or a chisel with a hammer is the next simplest method. This is another low-tech, economical method, but it comes with the same disadvantages as the first technique.
To use a chisel with a hammer, stabilize your geode somehow, by bracing or clamping it to a hard, stable surface. By using a chisel, you can concentrate the force of your hammer on a smaller surface, scoring a line around the outside of your geode to facilitate a clean break. If you are simply using a hammer, you may end up smashing the geode into many small pieces, so using a chisel with a hammer is recommended.
More Advanced Techniques
Another way to open a geode is with a power saw. This method should only be attempted by adults or with adult supervision. Use a rock or tile saw – something with a diamond blade – to create a clean cut down the center of the geode. The advantage of this approach is that you end up with two perfect halves to display, or one to keep and one to sell or share.
Disadvantages of using a saw include the cost of equipment and the safety risks. If your geode is small, it may not be safe to attempt to cut it open with a power saw, so use good judgment.
An iron pipe cutter is a tool that can be used for opening geodes, but it is a fairly specialized piece of equipment that can be quite expensive. Basically, a pipe cutter can be used to crack a geode by applying force to a chain that is wrapped around the outside of the geode. This method creates a clean cut, but it can send the pieces flying when the geode breaks in half. This is another technique that should only be attempted by adults or under adult supervision.
Geode Crystal Types
Geodes come in a wide range of sizes and colors. Most often, they are spherical or oblong. Created over many thousands of years inside other rock formations, geodes can usually be removed in one piece from their surrounding rocks. Geodes are often found in desert climates, but they can form in any environment where there is the ideal combination of minerals, temperatures, pressure and moisture.
The crystals that form inside of the outer shell of a geode are usually composed of agate and quartz. Minerals like iron oxide, cobalt, titanium, manganese and nickel can color the crystals red, blue, green or pink. Sometimes, the quartz crystals are purple. Purple quartz is also known as the gemstone amethyst, and it is the most valuable type of quartz.
Discovering what's inside a geode can be a fun and exciting process. Just remember to practice safety procedures while opening a geode, and put your safety goggles on before you even lift a hammer!
- Be sure to wear safety goggles and shard-proof gloves when breaking stone.
- Avoid simple hitting the geode heavily with a hammer as this will shatter the stone and destroy any crystallization on the interior.
About the Author
Meg Schader is a freelance writer and copyeditor. She holds a Bachelor of Science in agriculture from Cornell University and a Master of Professional Studies in environmental studies from SUNY College of Environmental Science and Forestry. Along with freelancing, she also runs a small farm with her family in Central New York.
Antonio Gonzalez Cuesta/iStock/Getty Images