“Sheared and finely folded valleriite fracture filling in association with some minor magnetite crystals (bright) in calcite matrix (medium to dark grey). The grain boundaries within the valleriite aggregates are illustrated by the strong pleochroism from brown to grey. Vertically reflected plane polarized light digital image in air, width of image 0.2 mm. Please note: valleriite (average hardness 1.25) is softer than graphite (average hardness 1.75). Due to the hexagonal layer lattice structure, valleriite, like graphite, is extremely sensitive to mechanical stress during grinding and polishing. Characteristically, some crystal orientations appear poorly polished. Ore microscopy is the only method that illuminates the opaque grey ugly with true reflectance colors. G. Grundmann collection and photo. ”

“Valleriite fracture filling in association with minor magnetite crystal (dark) in calcite matrix (dispersed light internal reflections). Vertically reflected plane polarized light digital image in air, with crossed polarizers, width of image 0.2 mm. Please note: valleriite (average hardness 1.25) is softer than graphite (average hardness 1.75). Due to the hexagonal layer lattice structure, valleriite, like graphite, is extremely sensitive to mechanical stress during grinding and polishing. Characteristically, some crystal orientations appear poorly polished. Ore microscopy is the only method that illuminates the opaque grey ugly with true reflectance colors. G. Grundmann collection and photo. ”