Onyx - Gemstone for Concentration and Courage

Onyx is a very popular semiprecious stone. It is a banded variety of Chalcedony Quartz usually black or brown with white bands. Onyx is widely used as an astrological gemstone. The name of this stone seems to have come from the Greek word onux which means finger nail or claw. This stone is effective in all Chakras and is used to treat heart, kidney, and nerve and eye ailments. This stone is also especially good for those who are under stress and have trouble sleeping.