By editor
Madison County
The Tobacco Root Mountains are a complex of ancient metamorphic rocks. East of the Ruby River, in the Greenhorn Mountains, the bedrock is schist, heavily studded with almandine garnets. As the mountains erode, the creeks carry these dense, dark red stones down into the valley, depositing them in the gravel bars of the Ruby River. Early miners, seeing the red flashes in their gold pans, mistook the stones for rubies.
Visitor Access
The public BLM lands south of Alder, particularly around the Ruby Reservoir, are free and open year-round. Rockhounds can walk the shorelines and collect up to twenty-five pounds of garnets per day using hand tools. The area also offers excellent fishing and camping.