8mm diameter 14k plated steel Hypo allergenic. Onyx is the “Gem of Saturn.” Saturn is the planet of Karma, which is the ruler of the universal law of cause and effect. Onyx is a type of stone under the Chalcedony family. It is usually a black stone, but brown, pink, red, and green Onyx stones. These gemstones also have a colorless variety. Onyx stone is a powerful and defensive stone that will aid you in dealing with your opponents in any confrontation. Onyx can bring you into the future and, because of its ability to instill personal courage, it will assist you in being the master of your fate. Onyx stone, the same as the Carnelian stone, encourages vigor, perseverance, and endurance. It aids in the learning of lessons by instilling self-assurance and making you feel at ease in your surroundings.