Chalcopyrite, pyrite, marcasite, sphalerite and pyrargyrite. Great Bear Lake, Canada
This is a sulphide skarn. Pyrite (yellow-white, bottom right) is intergrown with marcasite (white to light pink-white, centre bottom), showing strong reflection pleochroism and bireflectance (centre). A lath-shaped marcasite aggregate (top left) is a pseudomorph after pyrrhotite. Chalcopyrite (yellow, top) is intergrown with inclusion-free sphalerite (light grey, centre) and minor pyrargyrite (blue, centre, top left). Dark grey areas are silicate.
Polished block, plane polarized light, x 160, oil