For twelve rewarding stops, the backroads of Colorado turn dirt, stone, and time into an adventure well worth every dusty mile. What draws rockhounds here is the combination of mica books and quartz scattered along the trail near the historic mine site. Marshall Pass Western Railroad GradeThere is something quietly thrilling about rockhounding along an old railroad grade. Quartz Creek Pegmatite DistrictFew rockhounding destinations on the Western Slope carry the mineral diversity of the Quartz Creek Pegmatite District. The published directions start where the trail crosses the creek, followed by a half-mile walk upstream to reach the productive zone.