Niccolite, native silver, acanthite and maucherite. Great Bear Lake, Canada
Native silver (white, scratched, centre left) forms the cores to botryoidal niccolite (pink-brown) showing faint reflection pleochroism (light to dark pink-brown, centre right) that is difficult to see. Thin rims of maucherite (grey-blue, centre bottom) surround niccolite. Acanthite (light grey, bottom right) has replaced native silver in the core of a niccolite dendrite. Dark grey areas are calcite showing faint bireflectance (top centre). Black areas are polishing pits.
Polished block, plane polarized light, x 80, air