Ключевые слова: agate, chalcedony, crosssection, decorative, gem, gemology, gemstone, geode, geology, jewelry, marcasite, mineral, natural, ornamental, oxides, pattern, pebble, rock, rosequartz, semi precious stone, semiprecious, shape, shooting, silica, smokyquartz, specimen, stalactite, stone, textured, tumbled,