Kyanite is a typically blue aluminosilicate mineral, found in aluminium-rich metamorphic pegmatites and sedimentary rock.

[5] Kyanite is strongly anisotropic, in that its hardness varies depending on its crystallographic direction.

Kyanite is used as a raw material in the manufacture of ceramics and abrasives, and it is an important index mineral used by geologists to trace metamorphic zones.

[6] Kyanite's elongated, columnar crystals are usually a good first indication of the mineral, as well as its color (when the specimen is blue).

[6] The kyanite structure can be visualized as a distorted face centered cubic lattice of oxygen ions, with aluminium ions occupying 40% of the octahedral sites and silicon occupying 10% of the tetrahedral sites.

There is no direct linkage between the silica tetrahedra, making kyanite a member of the nesosilicate class of silicate minerals.

[6] Kyanite occurs in Manhattan schist, formed under extreme pressure as a result of a continental collision during the assembly of the supercontinent of Pangaea.

Kyanite is used primarily in refractory and ceramic products, including porcelain plumbing and dishware.

[19] At temperatures above 1100 °C, kyanite decomposes into mullite and vitreous silica via the following reaction: This transformation results in an expansion.

[19] Kyanite has been used as a semiprecious gemstone, which may display cat's eye chatoyancy, though this effect is limited by its anisotropism and perfect cleavage.