Mineral Type - Kyanite
Common metamorphic silicate mineral. The generally bluish colour is caused by Fe(II)-Fe(III) charge transfer (Faye and Nickel, 1969).
Transparency: Transparent, Translucent. Somewhat pearly on {100} || to the perfect cleavage
Colour: Blue, white, light grey, green, rarely yellow, orange, pink
Streak: Colourless
Hardness: 5½ - 7 on Mohs scale. 5.5 parallel to [001], 7 parallel to [100]
Tenacity: Brittle
Cleavage: Perfect. Perfect on (100), good on (010)
Parting; On (001)
Fracture: Splintery
Density: 3.53 - 3.67 g/cm3 (Measured) 3.67 g/cm3 (Calculated)
Elements listed: Al, O, Si
Class (H-M): 1 - Pinacoidal
Space Group: P1
Morphology: Crystals bladed or tabular
Twinning: Lamellar on (100), common
Name
Named in 1789 by Abraham Gottlieb Werner from the Greek word "kyanos", meaning "blue," the common colour of the species. The French spelling, "Cyanite", was commonly used by mineralogists through much of the 19th and early 20th centuries.Physical Properties
Lustre: Vitreous, Sub-Vitreous, Greasy, PearlyTransparency: Transparent, Translucent. Somewhat pearly on {100} || to the perfect cleavage
Colour: Blue, white, light grey, green, rarely yellow, orange, pink
Streak: Colourless
Hardness: 5½ - 7 on Mohs scale. 5.5 parallel to [001], 7 parallel to [100]
Tenacity: Brittle
Cleavage: Perfect. Perfect on (100), good on (010)
Parting; On (001)
Fracture: Splintery
Density: 3.53 - 3.67 g/cm3 (Measured) 3.67 g/cm3 (Calculated)
Chemical Properties
Formula: Al2(SiO4)OElements listed: Al, O, Si
Crystallography
Crystal System: TriclinicClass (H-M): 1 - Pinacoidal
Space Group: P1
Morphology: Crystals bladed or tabular
Twinning: Lamellar on (100), common