Rockhounding Materials & Finds

Agate

Banded chalcedony documented at four BLM and state-park sites across Arizona, California, and New Mexico — usually alongside jasper rather than as the sole draw, which makes it one of the more reliably present materials on this site's rockhounding pages even when it isn't a site's headline attraction.

Documented at 4 sites

Copper Minerals (Chrysocolla, Malachite & Azurite)

Blue-green copper minerals — chrysocolla, malachite, and azurite — turn up together at three Arizona and Utah sites, all tied to historic mining districts. One site's material comes from active copper mineralization; another's is a byproduct of old mine tailings, a distinction worth knowing before you go looking.

Documented at 3 sites

Geodes

Hollow, crystal-lined nodules — distinct from the solid thunder eggs covered separately on this site — documented at four BLM sites across Arizona, California, and Utah, with Dugway Geode Beds in Utah standing out for a genuine range of interior crystal types in one deposit.

Documented at 4 sites

Jasper

The single most widely documented material on this site's rockhounding pages — eight sites across five states report it, from Oregon's picture jasper (patterned with dendritic iron inclusions that resemble landscapes) to plain red and yellow varieties common across Arizona's open desert.

Documented at 8 sites

Obsidian

Volcanic glass documented at four sites across Oregon, Utah, and New Mexico — from Glass Buttes' four collectible varieties (including rare fire obsidian) down to the small rounded Apache tears found in New Mexico gravel. One recurring legal wrinkle: at sites with a long history of Native American toolmaking, worked obsidian is federally protected and cannot legally be collected even where raw material is free to take.

Documented at 4 sites

Opal

Three Nevada and Oregon sites document opal — and between them show the full range of access this material can have: free on open BLM ground, available at a paid fee-dig claim, and documented but genuinely inaccessible to the public at a private, patented deposit that only looks like a BLM site on casual rockhounding lists.

Documented at 3 sites

Petrified Wood

The same material, three completely different legal outcomes: fully protected and visible-only at Petrified Forest National Park, and freely collectible under standard BLM personal-use rules at two other documented sites in Arizona and Nevada.

Documented at 3 sites

Thunder Eggs

Thunder eggs are rhyolite nodules — solid, not hollow like a true geode — that formed as gas cavities filled with agate, chalcedony, jasper, or opal. Four sites document them across Oregon, Nevada, and New Mexico, and one, Succor Creek, is considered the signature Oregon locality for the material.

Documented at 4 sites