Geodes
Geodes are Mother Earth's mystery gift; only when you open them up will you know what you've got. Formed in sedimentary or volcanic rock, they may contain crystals of clear quartz, amethyst, calcite or, more rarely, pyrite, sphalerite, celestite or other minerals.
Here you'll find whole geodes, which you can slice or break open yourself with lapidary equipment or a crack hammer, as well as sliced and face polished geodes, geode halves and geode fragments. Also check out our books on rockhounding.