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