“The microstructure of high-grade silver ore from Randsburg, California. What does silver ore from Randsburg really look like? Full views of fine-grained ore specimens from Randsburg only show indefinable blackish-metallic masses. Exact mineral detection and identification is absolutely impossible on the basis of those pictures. Only the examination in the vertically reflected light ore microscope enables the determination of the natural reflectance colours and microstructure. Detail of an ore fragment embedded in resin. Slightly porous crystals of pyrite (spotty pale yellow), in association with miargyrite (pale blueish greys) and fine-grained aggregates of subhedral arsenopyrite crystals (cream white), in fine-grained matrix of calcite and quartz (dark grey to black). Vertically reflected plane polarized light digital image in air. Please compare the corresponding photomicrographs. G. Grundmann collection and photo. ”

“The microstructure of high-grade silver ore from Randsburg, California. What does silver ore from Randsburg really look like? Full views of fine-grained ore specimens from Randsburg only show indefinable blackish-metallic masses. Exact mineral detection and identification is absolutely impossible on the basis of those pictures. Only the examination in the vertically reflected light ore microscope enables the determination of the natural reflectance colours and microstructure. Detail of an ore fragment embedded in resin. Slightly porous crystals of pyrite (spotty isotropic), in association with miargyrite (strong blueish to brownish anisotropy with few red internal reflections) and fine-grained aggregates of subhedral arsenopyrite crystals ((red brown to blue anisotropy), in fine-grained matrix of calcite and quartz (various dispersed light internal reflections). Vertically reflected plane polarized light digital image in air, with crossed polarizers. Please compare the corresponding photomicrographs. G. Grundmann collection and photo. ”