Geode Hunting: Finding Hidden Treasure

A geode is a hollow rock lined with crystals. They start as bubbles in volcanic rock or cavities in sedimentary rock. Over time, mineral-rich water seeps in and deposits crystals like quartz, calcite, or amethyst on the inside walls.

Geodes often look like ugly, lumpy potatoes on the outside. They are typically spherical or cauliflower-shaped. In a bed of sedimentary rock, look for the round rocks that don't quite match the surrounding layers.

Because they are hollow, geodes are lighter than solid rocks of the same size. Pick up several similar-sized rocks; the light ones are your best candidates for being hollow.

The safest way is a soil pipe cutter (a chain tool that snaps them evenly). You can also use a hammer and chisel to carefully work around the circumference. Smashing them with a sledgehammer often shatters the delicate crystals inside.