Kyanite is a metamorphic mineral, not a rock. It is a member of the silicate mineral group and is known for its characteristic blue color, although it can also occur in green, gray, or white varieties. Kyanite forms under high-pressure, high-temperature conditions during the metamorphism of sedimentary rocks.
Kyanite's distinctive property is its anisotropy, meaning it exhibits different hardness and crystallographic directions along its three axes. This anisotropic property makes it valuable in industrial applications, such as manufacturing refractory materials and high-temperature ceramics. Additionally, kyanite is sometimes used as a semiprecious gemstone in jewelry when cut and polished into attractive shapes.