Getting ready to rock in Ohio
If you want to see cool geodes, Ohio has the largest one in the world on display. If you want to rummage around yourself and find some geodes, Ohio may not be the best choice. Here are answers to frequently asked questions about geodes and where to find them.
Q: What is a geode?
A: Geodes look like round rocks on the outside. But when they are cracked open, the inside is a hollow cavity that is lined with crystals. If the cavity is completely filled with crystal formations, the rock is called a nodule rather than a geode.
Q: How are geodes created?
A: Geodes can start life as bubbles inside volcanic magma or as other rock deposits in scooped out areas like animal burrows. Over millennia, an outer shell of rock hardens into the bubble or hollow. As rain falls, rainwater picks up silica that seeps into the hollow. The silica can contain quartz or other dissolved minerals that line the inner walls of the hollow forming crystals inside.
No two geodes are alike since the mineral-forming crystals are different. The crystals can be different colors and sizes. You can't tell until you open the geode.
Q: How do you open geodes?
A: You have to open geodes to see the crystals inside. How do you open them? You can place the geode inside a sock and hit it on something very hard. But you are likely to end up with many fragments instead of a clean break. Sawing a geode open allows for clean breaks and a pretty display. Some folks saw geodes with a soil pipe cutter. Treasure hunters preferring a natural look use a chisel and hammer that gives a natural break, leaving the crystals intact.
Q: What is the best type of terrain for geode hunting?
A: The entire globe is your foraging ground when looking for geodes, since you might find one almost anywhere. But deserts, volcanic ash beds and regions with limestone tend to have the most geodes. In the United States, you'll find good geode areas in California, Arizona, Iowa, Utah and Nevada. If you are in Southern California, you'll find good concentrations of geode sites in Riverside and Imperial counties. Hauser Geode Beds is perhaps the most famous. It's located at Wiley Well in the north Imperial Valley.
Q: Are there lots of geodes in Ohio?
A: Ohio is not a hot spot for geodes. That doesn't mean you won't find any, but you don't have immediate go-to spots. Findlay Arch mineral district in northwestern Ohio has crystal geodes with minerals including calcite, celestite, dolomite and fluorite inside. But it's hard to find natural outcrops in this glaciated area. Most geode finds have been in quarries that are not open to the public for collecting.
Another place with geodes in Ohio is an area in the southern parts of the state in Adams and Highland counties. Called the Serpent Mound zinc district, it's home to some geodes containing calcite and barite.
Crystal Cave in Ohio is called the world's largest geode. It's located in a town called Put-in-Bay on South Bass Island. It was discovered over 100 years ago and is located 40 feet below the earth's surface. The geode cave is in places 35 feet in diameter and contains crystals weighing up to 300 pounds.
Q: Do you need any special license or documents to look for geodes?
A: You'll need permission from a landowner to enter land owned by someone other than yourself and certainly to treasure hunt there. But no geode licenses or permits as such are required.