Mineral - Black Kyanite

Name Kyanite
Class Nesosilicates
Category Mineral
Crystal system Triclinic
Chemical composition Aluminum silicate (Al₂SiO₅)
Hardness (Mohs scale) 4.5 to 5 (parallel) / 6.5 to 7 (perpendicular)
Transparency Translucent to transparent
Geographical origin Brazil, Nepal, United States, India, Switzerland, Kenya