Quartz — The Universal Find
Clear quartz crystals grow in six-sided prisms and are found on every continent. In the US, Arkansas produces world-class clusters from hydrothermal veins. Look for quartz in pegmatites, granite outcrops, and along creek beds where crystals weather out of the host rock.
Amethyst — Purple Quartz
Amethyst is simply purple quartz, colored by iron impurities. Thunder Bay, Ontario is famous for it, but the US has great deposits in Arizona, North Carolina, and Maine. Geodes cracked open in Iowa and Illinois regularly reveal amethyst cores.
Agate — Banded Chalcedony
Agates form when silica-rich water fills volcanic gas bubbles over millions of years, creating concentric banding. Lake Superior agates, Oregon's thunder eggs, and Montana's sapphire gravels are among the best. Look in gravel bars and stream beds.
Garnet — Red Crystals in Metamorphic Rock
Garnet commonly appears as dark red dodecahedral crystals embedded in schist and gneiss. Idaho's star garnets, North Carolina's rhodolite garnets, and Vermont's grossular garnets are well-known finds. Look for them where metamorphic rocks have been exposed by erosion.
Pyrite — Fool's Gold That's Worth Finding
Pyrite's perfect cubic crystals and metallic gold luster make it one of the most visually striking mineral finds. Colorado, Virginia, and Illinois produce excellent specimens. It won't make you rich, but a well-formed pyrite cube is a prize piece in any collection.
Obsidian — Volcanic Glass
Obsidian forms when lava cools so fast that crystals don't have time to grow, producing a natural glass. Oregon, Idaho, and California have excellent obsidian flows on public land where collecting is permitted. Look for Rainbow Obsidian and Mahogany Obsidian varieties.
Fluorite — The Most Colorful Mineral
Fluorite comes in purple, green, yellow, blue, and colorless — sometimes all in one crystal. Illinois is the "Fluorite Capital of the World" and has dedicated fee-dig operations. Kentucky and Colorado also produce excellent specimens from hydrothermal veins.