Ключевые слова: anthracite, bituminous, bituminous coal, black, black coal, carbon, close up, coal, collection, decorative, gemmological, gemmology, gemological, gemology, gemstone, geological, geology, gray, gray background, little, macro, macro shooting, material, mineral, natural, object, ore, ornamental, piece, raw, rock, rough, sample, sedimentary, small, specimen, stone, surface, texture, textured, white, white background,