“Reflected light digital image in plane polarized light of fine-grained athabascaite (bluish), which shows a network of shrinking cracks penetrates krut'aite-penroseite solid solution aggregate (athabascaite identified by microprobe analysis). For further explanations see reference: Origin of the El Dragón Selenium Mineralization, Quijarro Province, Potosí, Bolivia. Günter Grundmann and Hans-Jürgen Förster, published in: Minerals 2017, 7, 68; doi:10.3390/min7050068 G. Grundmann collection and photo. ”