Rockhounding Colorado

Where to find crystals in Colorado

Where to find crystals in Colorado comes down to two kinds of rock: pegmatites and veins. Pegmatites are bodies of extremely coarse granite, and the open pockets inside them are where free-standing crystals had room to grow; they give Colorado its amazonite, smoky quartz, topaz and aquamarine. Veins are cracks filled by hot fluids, and they gave the mining districts their quartz, pyrite, fluorite and rhodochrosite. The Denver Gem and Mineral Guild keeps a list of collecting sites, and local clubs run field trips with owners' permission. For the minerals themselves, start with Colorado gemstones.

Pikes Peak amazonite and smoky quartz

Pikes Peak amazonite and smoky quartz come from pegmatites in the Pikes Peak granite, a body of rock more than a billion years old that spreads west of Colorado Springs. Blue-green amazonite with dark smoky quartz is one of the classic American mineral pairings, and the country around Crystal Peak, Lake George and Florissant is famous for it. Much of that ground is covered by active mining claims, some of which run fee digs, and the Pike National Forest land between them follows Forest Service rules.

Mount Antero aquamarine

Mount Antero aquamarine comes from pegmatite pockets high on the mountain and on neighboring White Mountain in Chaffee County, much of it above 13,000 feet. Antero gives pale to deep blue aquamarine, smoky quartz and rarer minerals like phenakite. It is serious country: a rough four-wheel-drive road, thin air, loose talus and lightning that often builds by early afternoon in summer. Many of the best spots are active claims, so check claim status before you collect.

Sweet Home Mine rhodochrosite

Sweet Home Mine rhodochrosite is history now, not a place to dig. The mine, on Mount Bross near Alma in Park County, opened in the 1870s as a silver mine, and early miners treated its red rhodochrosite as waste. Specimen miners reopened it in 1991 and recovered some of the finest rhodochrosite ever found, including the Alma King, now on display at the Denver Museum of Nature & Science. The mine is closed and on private land. Rhodochrosite became Colorado's state mineral in 2002, and Wikipedia's Sweet Home Mine article has the longer story.

Colorado rockhounding rules

Colorado rockhounding rules start with who owns the ground under your boots. Use a land ownership map, and when in doubt, leave it in the ground.

Private land: you need the owner's permission, every time.
Mining claims: an active claim on public land gives the holder the mineral rights, so collecting there without permission is theft. Patented claims are private land.
National parks and monuments: no collecting, including at Florissant Fossil Beds National Monument.
State parks and wilderness areas: separate rules apply, so check before you go.
Fossils and artifacts: vertebrate fossils and archaeological artifacts on public land are protected. Leave them where they lie.

BLM and Forest Service land

BLM and Forest Service land is where most public collecting happens, and both agencies generally allow small amounts of rocks and minerals to be collected by hand for personal use without a permit. The Bureau of Land Management calls this casual collecting: reasonable amounts, hand tools, little disturbance and no selling. National forests set their own rules forest by forest and district by district, so call the local ranger district before a trip. Neither agency lets you collect on someone else's claim, and the BLM's Colorado mining and minerals page has the agency's Colorado details.

Crystal hunting in Colorado: staying safe

Crystal hunting in Colorado happens at altitude, so plan around the weather first. Start early, get off high ridges before afternoon storms, carry water and layers, and tell someone where you are going. Wear safety glasses when you swing a rock hammer. Stay out of old mine tunnels and shafts, which can hold bad air, rotten timbers and hidden drops. Fill your holes and pack out what you pack in. The USGS guide to collecting rocks covers the basics of the hobby.