mineral

Kyanite

Kyanite (Al2SiO5)

AI-generated identification · may be incorrect

Hardness varies significantly depending on the direction: 4.5 to 5 parallel to the length, and 6.5 to 7 across the blade. Typically blue, but can be white, gray, green, or black. Vitreous to pearly luster. Triclinic crystal system, usually forming distinct bladed crystals.

Identified July 29, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in aluminum-rich metamorphic pegmatites and gneiss resulting from the dynamic metamorphism of argillaceous sediments under high pressure.

Uses & applications

Used in the manufacture of refractory products, ceramics, porcelain plumbing fixtures, and occasionally as a gemstone in jewelry.

Geological facts

Kyanite is one of the best examples of anisotropy in minerals, having distinctly different physical hardnesses depending on which direction you scratch it.

Field identification & locations

Easily identified by its characteristic bladed crystal habit, distinct blue coloration, and extreme hardness anisotropy. Found worldwide, notably in Switzerland, Brazil, USA, and Nepal.