“The fascinating internal structures of the Grüneau Mine (type locality) polydymite mineralization: Tiny inclusion of gold (bright yellow, centre) in strongly fractured polydymite crystals (crème-grey), with bismuthinite inclusions (blueish-grey), showing a finely distributed network of shrinkage cracks, cemented by chalcopyrite (dark-greenish-yellow) and covellite (blue). Vertically reflected light digital image, width 0.2 mm. Please compare the corresponding photomicrographs. Ore microscopy illuminates the darkness of the opaque “grey-ugly” with true reflectance colours. G. Grundmann collection and photo. ”