Rock hobbyists from all over the United States will set up outdoors and under tents to sell or swap rock and mineral specimens, fossils, rock jewelry and other rock-related items. The public is invited and all are encouraged to participate. The historic site’s museum will be open free of charge during regularly scheduled hours throughout the event. Auctions of donated rock-related items will be conducted daily to benefit the site's mineral museum.
Missouri Mines State Historic Site co-hosts the rock swap with the Mineral Area Gem and Mineral Society and the Greater St. Louis Association of Earth Science Clubs.