Uraninite and chalcopyrite. Port Radium, Northwest Territories, Canada
Coarse botryoidal uraninite (light grey, bottom) is accompanied by smaller botryoidal uraninite, 'blasenblende' (top). Chalcopyrite (yellow, centre bottom) lies along fractures and shrinkage cracks of the uraninite. The carbonate gangue shows bireflectance (top left).
Polished block, plane polarized light, x 40, air