Ключевые слова: allotrope, bituminous, black, black batt, bony coal, brown, burnable bone, carbon, carbonaceous, close up, coal, collage, collection, crystalline, cut out, cutout, gagate, gem, gemstone, geological, graphite, gray, industrial, isolated, jet, lignite, material, mineral, mineraloid, native, natural, nugget, piece, plumbago, polished, raw, rock, rough, sample, sedimentary, set, shale, shungite, slate, stone, tumbled, tumbling, various, white, white background,