Black Kyanite is a high vibration mineral that is also wonderfully grounding. It is rarer than blue kyanite, and it is one of the only black stones I know of that does not absorb negative energy as part of its function. It clears all of the chakras, and is particularly effective with the base chakra.
Aso called Witches Broom because of it's shape, Black kyanite is a fantastic stone for mitigating the effects of Mercury retrograde , encouraging mental clarity and helping to reduce anxiety and stress. It is also said to assist in getting a good night's sleep.