Covellite
Summitville Mining District, Rio Grande County, Colorado, USA
Precipitation of covellite in the South Mountain quartz latite (within the Platoro-Summitville caldera) followed a sulfate alteration/silicification event at low pH (Stoffregen 1987; Gray and Coolbaugh, 1994). In this large vug, some alunite-quartz (visual ID) can also be seen overgrowing covellite and elsewhere on the specimen, © Tony Peterson