Blue Kyanite

Hardness: 4.5 to 7 on the Mohs scale (anisotropic, varying drastically along different crystal axes); Color: Typically blue, ranging from light to dark, sometimes white, gray, or green; Luster: Vitreous to pearly; Crystal Structure: Triclinic, forming elongated, blade-like crystals; Cleavage: Perfect in two directions; Specific Gravity: 3.53 to 3.67.

Forms primarily in aluminum-rich metamorphic pegmatites and/or gneiss resulting from regional metamorphism of clay-rich sediments under high pressure.

Used in the manufacture of refractory products, ceramics, electrical insulators, and occasionally cut into cabochons or used as mineral specimens by collectors.

Kyanite is one of the classic index minerals used by geologists to determine the temperature and pressure conditions under which a rock underwent metamorphism.

Easily identified by its distinct blade-like crystal habit, strong blue color, and characteristic variable hardness (scratched easily parallel to the length of the blade, but harder across the width). Found worldwide, including Brazil, Switzerland, Russia, Kenya, and the USA.