Tourmaline (Black) Raw SLABBlack tourmaline has been used since ancient times by Shamans and healers for protection. Black Tourmaline is considered by many to be the most powerful protective stone and it is one of the only stones that protects and heals on all levels physical, emotional, mental and spiritual. Following are just some of its incredible benefits: Protects from negative energies transmutes negative energies of all kinds (including thoughts) into positive energies.