The above video shows how to crack a Geode with a 36" chain commercial soil Pipe Cutter. The Geode is approximately 8 inches in diameter. The chain is wrapped around the circumference of the Geode and tightens gradually until the shear forces breaks the Geode in half. This particular Geode was found in Indiana and was not a "rattler".
The Pipe Cutter works by creating a circle of pressure points around the circumference of the Geode. As the levers are compressed the chain tightens and the points etch the Geode with tremendous pressure. Repetition of compression and tightening of the soil Pipe Cutter chain results in distributed pressure around the exterior of the Geode. Ultimately, the Geode breaks along the pressure point line and creates a piezoelectric spark which can be clearly seen in the video.
Cracking Geodes is hard work but lots of fun! Learning the best way to crack a Geode takes practice. Whether you try your hand at using a custom Geode cutter, wet saw, or a simple chisel always wear eye protection and be careful. Discover the rewards of Geode hunting outdoors.
Get out and rockhound!