"1. Onyx comes from a Greek word ’onux’ which means Fingernail. The onyx chemical formula is SiO2.It is quartz crystals and naturally obtains from rocks. 2. Green Onyx is an astrological substitute for Emerald Gemstone and related to Planet Mercury. Good to help people improve their public speaking ability. 3. Green Onyx Gemstones has been used in jewelry because of its rich looking. 4. Benefits - Green Onyx is associated with Heart Chakra and the planet Mercury. Green Onyx attracts positive energy and repels negative energy and it is beneficial for all chakra. "