NAUMANNITE from Washington State
Ag2Se


 
ELECTRUM grains within dark gray bands of NAUMANNITE and white QUARTZ (Var: Chalcedony)
Knob Hill Mine (Golden Promise Mine)
 
Slab of banded Au-Ag ore with NAUMANNITE and QUARTZ (Var: Chalcedony)
Knob Hill Mine (Golden Promise Mine)