- Recreation Area, Rockhounding
- General info
Crystal Park is a unique recreation area at an elevation of 7,800 feet in the Pioneer Mountains in southwest Montana. The Butte Mineral and Gem Club maintain mining claims at Crystal Park open to the public for digging quartz crystals (rockhounding in Montana). You are welcome to dig for quartz crystals here but are asked to follow the rules of the Park. The park is open from May 15 through October 15, but those dates are subject to change depending on snow and road conditions. There is no charge, although donations for support of operations and maintenance of the site are welcome.
Like most of the eastern Pioneer Mountains, the “country rock” or bedrock at Crystal Park is granite. About 68 million years ago, the Pioneer Batholith intruded the area, pushing up molten granite to form the Pioneer Mountain range. The granite was about 300º C or approximately 600º F. As the granite cooled, super-heated water circulated through it, carrying quartz, pyrite, and other minerals in solution. As the granite and the water continued to cool, the minerals precipitated out and were deposited in veins and cavities (called “vugs”). The molten granite continued to cool and