Vertus De L'onyx or Black Agate :
First of all, this stone is a variety of black and white Chalcedony. This is the black part, generally called Black onyx. On the one hand, it is a mineral anchor to the Earth. In addition, Onyx is also a stone of knowledge. Also like the majority of black stones, onyx is a very good protective stone.
Tradition and Symbolism :
Tradition : Protection
. Chemical composition: silicon dioxide