Kyanite
Kyanishi (kananite, kayanite, kaya knight) is a kind of mineral. Composition is aluminum silicate (Al 2 SiO 5). Specific gravity 3.6. Mohs hardness 4 to 7.5. Triclinic system. Minerals with high hardness anisotropy. With the same chemical composition, there are other red and black stones and siliceous stones as polymorphism (relation of homosexuality). Kyanite is a stable crystalline form under high pressure. ...