This necklace has carved "Yin & Yang" symbol in Black Obsidian stone making it very powerful protection pendant.

Black Obsidian is a natural volcanic glass that has exceptional healing properties.
One of the most powerful stones of nature, It increases the life force, gives energy, brings opportunities and cleanses the psychic fog created by your aura.

Black Obsidian can be used as grounding and protective agent. 
It has powerful metaphysical properties that will help to shield you against negativity.
Obsidian helps people surrender or let go of negative habits or past pathways that no longer serve their present condition. 

It can bring about the opportunity for change, serenity, and clarity.

Yin and Yang is the symbol representing the two fundamental principles of Chinese philosophy. Complementary, they represent duality: the two extremes of a whole and coexisting together.