Onyx Gemstones : Onyx Gemstone is one of the most intriguing stones you may encounter. It is a Chalcedony mineral that contains a hardness of 7. It is the zodiac sign of Leo and the birthstone of Capricorn. Since its discovery, it has been a famous stone, ever since its dictionary. It was extremely popular among ancient Greeks and Romans. They believe it removes negative cosmic energies.
