Kyanite is a very complicated gem to cut. Its Mohs' Hardness is two ways, i.e. Along axes 4-41/2 and across 6-7. Gem cutting is anyways an art of good concentration and kyanite needs to be cuts with a lot of it.
Name Kyanite came from its color. It has a vitreous luster, often with irregular streaks. Difficult to cut because of variable hardness. Its a Aluminium silicate Material, usially found in Sedimentary rocks.
In Alumino Silicare series also includes the polymorph andalusite and the polymorph siliminite . Kyanite is strongly anisotropic, in that its hardness varies depending on its crystallographic direction. In kyanite, this anisotropism can be considered an identifying characteristic.
Kyanite is used primarily in refractory. and ceramic products, includingporcelain plumbing and dishware. It is also used in electronics.
Kyanite has been used as a semiprecious gemstones, which may display cat's eye chatoyancy though this use is limited by its anisotropism and perfect cleavage. Color varieties include recently discovered orange kyanite from Tanzania.The orange color is due to inclusion of small amounts ofmanganesein the structure.