Hetaerolite and chalcophanite, a nice example from the so-called “manganese zone” associated with the Passaic pit at Sterling Hill. Both species come from areas of severely weathered ore in near-surface environments and peripheral to permeable structures that allowed oxygenated groundwater to form oxidized-zone minerals deeper underground. The Passaic pit is the surface expression of a solution-collapse breccia pipe, an effective permeability conduit. Rock in and adjacent to the pipe is highly weathered and rich in secondary minerals, a variety of manganese oxide minerals among them.