Ключевые слова: abstract, background, black, cluster, collection, crystal, crystalline, dark, dark background, dark stone, faceted, faceted surface, formation, geological, geology, geology background, geometric, grey, group, igneous, mineral, mineral cluster, mineral deposit, mineral specimen, mineralogy, natural, natural formation, obsidian, pile, raw, reflective, rock, rough, rough texture, sharp, sharp edges, sharp points, stone, structure, surface, texture, uncut, volcanic,