Ключевые слова: amethyst, barite, calcite, chalcedony, color, colorful, colour, crystal, crystalline, crystallography, crystals, cut, dolomite, formation, gems, gemstones, geode, geodes, geologic, geological, geology, half, inorganic, kaolinite, lattice, limonite, millerite, minerals, polished, pyrite, quartz, rock, sample, science, section, smithsonite, sphalerite,