Group: Silicates – neosilicates
Chemical composition: Al2SiO5
Colors: Blue, green.
Hardness: 4.5 to 6
Formation: Triclinic crystal; Bladed form
Principal Sources: Brazil,India,Kenya, Switzerland, North Carolina
Special Notes: The name of kyanite is from the Greek word kuanos sometimes referred to as “kyanos”, meaning deep blue. It is a typically blue silicate mineral, commonly found in aluminium-rich metamorphic pegmatites and/or sedimentary rock. Kyanite in metamorphic rocks generally indicates pressures higher than 4 kilobars. Although potentially stable at lower pressure and low temperature, the activity of water is usually high enough under such conditions that it is replaced by hydrous aluminosilicates such as muscovite, pyrophyllite, or kaolinite. It is a raw material for aluminum silicate mulite, used in spark plugs and heat resistant porcelains.