Approximate location — plotted from published sources, not a site visit, and not a guarantee of access.
Tonto National Forest geology and managed crystal-collection area on Diamond Rim northeast of Payson. Precambrian granite and metamorphic basement, Cambrian Tapeats shoreline deposits, and Devonian Martin Formation carbonates host cavities where doubly terminated quartz (“Payson diamonds”) grew; Redwall Limestone and Mogollon Rim strata complete the stack. USFS designates a 35-acre collection zone with strict hand-tool and 10 lb/person/day limits—field geology first, collecting only inside the mapped unit.