The unique geology of the Ochoco Mountains is such that a wide variety of rock types are located in a relatively small area. This brings rockhounds to the area every summer. The Bureau of Land Management and the Ochoco National Forest both have designated areas where rockhounds can search for agate, jasper, petrified wood, petrified moss, and dendrite. These rock collection sites are for personal use only; gathering rocks for commercial purposes is prohibited. Thundereggs can be found at Whistle Springs. Even though the area has been worked by rockhounds for many years, quality thundereggs are still found at the site. There are also some rare rocks and minerals in central Oregon in or near the Ochoco Mountains, including opals, amethyst, gem quality calcite, cinnabar, selenite, gypsum, and amygdaloid nodules.