Oregon — The Ultimate Rockhound State
Oregon may be the single best state in the country for variety and accessibility. Collect Oregon sunstones (free on BLM land), thunder eggs (designated fee and free areas), rainbow obsidian at Glass Buttes (free), precious opal at the Royal Peacock and Bonanza Mines (fee), and agate along the coast (free on beaches). The state gemstone, the state rock (thunder egg), and the state fossil are all collectible by the public.
Washington — Petrified Wood Paradise
Washington's Ginkgo Petrified Forest State Park near Vantage preserves 200+ species of petrified trees — though collecting is restricted in the park. Adjacent BLM land allows petrified wood collecting. The Olympic Peninsula has excellent agate beaches. Eastern Washington's Columbia Plateau has zeolite and chalcedony in the basalt flows. Banded agate nodules are found in creek gravels statewide.
Idaho — Star Garnets and Opals
Idaho has two world-class gem deposits: the Emerald Creek Garnet Area (star garnets — fee dig) and the Spencer Opal Mines (precious opal — fee dig). The Snake River Plain has extensive obsidian collecting areas. Panhandle Lakes region has excellent quartz crystal localities. Boise Basin still produces placer gold in its historic river gravels.
Coastal Agate Beaches
Oregon and Washington's Pacific coast has excellent agate collecting on public beaches — no permit required. The best beaches are south-facing coves that collect material during winter storms. Agate Beach near Newport, Oregon is legendary. Low tide after winter storms is the optimal time — look for translucent stones that glow when held up to the sun.
Thunder Eggs — Oregon's State Rock
Oregon thunder eggs are geode-like spherical nodules found in rhyolite flows. The outside is unimpressive but cutting reveals agate, jasper, and occasionally opal or chalcedony interiors. Oregon has numerous fee-dig operations (Richardson's Rock Ranch, Polka Dot Mine, Succor Creek) that sell or allow digging for thunder eggs.