Merkaba is the divine light vehicle allegedly used by ascended masters to connect with and reach those in tune with the higher realms. "Mer" means Light. "Ka" means Spirit. "Ba" means Body. Mer-Ka-Ba means the spirit/body surrounded by counter-rotating fields of light, (wheels within wheels), spirals of energy as in DNA, which transports spirit/body from one dimension to another. Black tourmaline crystals are ideal for keeping ones auric field clear of imbalances and even destructive energies. Part of sacred geometry and Kabbalistic practices.
Spiritually black tourmaline provides a grounding path for light to enter the Earth plane. Emotionally it helps one disengage from obsessive or compulsive behaviors and releases chronic worry and anxiety.