Geology of the Hugo pegmatite, Keystone, South Dakota

Abstract

Pegmatite units ____________________________________ Zone 1 : Albite-quartz-musco vite pegmatite ________ Zone 2: Quartz-albite-muscovite pegmatite. _______ Zone 3: Perthite-quartz-albite pegmatite, quartzperthite-albite pegmatite, albite-quartz-phosphate pegmatite, and quartz-albite pegmatite.-________ Zone 4: Quartz-cleavelandite-microcline-amblygonite pegmatite and quartz-cleavelandite* pegmatite