Kyanite is a aluminosilicate mineral with the chemical formula Al₂SiO₅. It typically appears in shades of blue, though it can also be found in green, gray, or white. Kyanite has a distinctive characteristic of having uneven hardness—ranging from 4.5 to 7 on the Mohs scale, depending on the crystal orientation. It is commonly found in metamorphic rocks such as schists and gneisses. Major sources of kyanite include Brazil, India, and the United States (North Carolina). It is used in refractories, abrasives, and occasionally in jewelry.