Molybdenite and native bismuth. Mount Pleasant, New Brunswick, Canada
Molybdenite laths (greys, centre) show bireflectance and reflection pleochroism and are well to poorly polished, with the degree of polishing dependent upon orientation. Discrete crystals of native bismuth (cream-white, top left) are soft (scratches) and show high reflectance. To the eye, the reflectance of bismuth is higher than the photomicrograph would suggest. The gangue comprises carbonates (lighter greys, centre left) and silicates (dark greys).
Polished block, plane polarized light, x 80, air