Arsenopyrite and native bismuth. Cornwall, Britain
Arsenopyrite (white, left) is fractured and contains lath-shaped inclusions of native bismuth (cream, high reflectance, centre). Quartz (grey, right) gangue is pitted. To the eye, the reflectance of bismuth is higher than the photomicrograph would suggest.
Polished block, plane polarized light, x 80, air