Onyx is a type of agate and agates are a type of chalcedony that comes in various colors. Black onyx is one of the most popular stones. This durable stone is an excellent choice for many types of jewelry.
Onyx is reputed to improve concentration and devotion. It is believed to help hearing problems and ulcers. It is considered a grounding stone that stimulate self-control.
It is mined in Brazil, Canada, the Czech Republic, Germany, Madagascar, the United Kingdom, the United States, and Uruguay.