Kyanite is an aluminum silicate and it belongs to the triclinic crystal system. kyanite has two different hardnesses. Long wise on the crystal has a hardness of 4-5 across the crystal is 6-7. Kyanite is usually found in a light blue color but can also be found in other colors such as white, colorless, gray, green, and nearly black. The Blue Kyanite in these pendants has a shimmering translucent look.