It has powerful metaphysical properties that will shield you against negativity. The energy of these stones may stimulate the gift of prophecy.
Pieces of these stones that had a shiny surface were used in the past as a tool for scrying.
It an excellent crystal to use when you have been doing spiritual or healing work, as it has a strong action to ground you to Mother Gaia.
This black stone is excellent to assist you to release disharmony that has built up in your day to day life and during work on yourself, including resentment of others, fear and anger.