Black Obsidian is a powerful cleanser of psychic disarray within your aura. This stone has not only strong psychic protection properties, but is is also a great shielder against general negativity.
There is also a tradition that this stone may stimulate the gift of prophecy and may boost precognition. Black obsidian is often used for scrying, and there is evidence that our ancestors used the shinny natural surfaces for divining work.
Obsidian is an awesome grounding stone and has many uses in spiritual haling workings. Obsidian has a good assisting energies to cut or sever ties, to break negative attachments to people, often working best in severing ties with whom you have been close.
This black stone is helps to release disharmony that has built up in your day to day life and during work on yourself. Also the feelings of resentment of others, fear, and anger.