Black Obsidian is a powerful stone for grounding and protection by shielding you from all negative energies.  It helps to clear confusion and bring clarity to your thoughts.  Blocks psychic attackes and any negative spiritual influences.  It gives you inner strength and confidence while balancing the energy of the body, mind and spirit.  Associated with the root chakra it helps to keep you grounded and tether you to the present
 
Chakra: Root