Green Kyanite is a variety of the silicate mineral Kyanite, usually found in aluminum-rich metamorphic pegmatites or sedimentary rock. Kyanite is anisotropic (directionally dependent) and so it's hardness depends on its crystallographic direction; being anisotropic is a defining characteristic of Kyanite.
Metaphysical: Kyanite is commonly used as a tool during meditation for attunement. It is a tranquilizing stone thought to be a powerful transmitter, amplifier of energies, and aligning all of the Chakras. Something unique about Kyanite is that it is not believed to hold negativity, meaning it never needs cleansing.