Obsidian

This stone can be difficult for some people to work with.  It is an excellent self-improvement stone allowing for reflection of ones flaws and promoting a clear picture of changes which are necessary to eliminate said flaws but does this very bluntly. It is a stone that provides "no B.S." answers, focusing on inner vision of self and a vision of the needed course of action.  It shields one against negativity, transforming negative vibrations within an environment.  Carrying or wearing it  further disperses those unloving thoughts which arise within the self or are directed towards ones physical form. It is an excellent protective stone, stabilizing internal and external energies and gently protecting one from that which could bring physical and/or emotional harm.  It is a grounding stone and provides for a connection from the base of the spine to the heart of the earth.  It's useful in healing, providing both healer and the subject clarity with respect to both cause and amelioration of disease.