Mineral

Blue Kyanite

Kyanite (Al2SiO5)

Hardness: 4.5-5.0 (along axes) and 6.5-7.0 (across axes). Color: Blue, white, cyan. Luster: Vitreous to pearly. Crystal Structure: Triclinic. Cleavage: Perfect in one direction. Specific Gravity: 3.53-3.67.

Hardness: 4
Color: Blue, white, cyan
Luster: Vitreous to pearly

Identified March 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed through high-pressure regional metamorphism of clay-rich sedimentary rocks. Typically found in mica schists, gneisses, and associated pegmatites. It is an index mineral for high-pressure environments.

Uses & applications

Used industrially in the manufacture of refractories (kiln furniture, spark plugs) and ceramics. Common in jewelry as cabochons and for metaphysical crystal collecting.

Geological facts

Kyanite is highly anisotropic, meaning it has two different hardness ratings depending on the direction it is scratched. This makes it difficult to cut as a gemstone. It is chemically identical to andalusite and sillimanite (polymorphs).

Field identification & locations

Identify by its distinct bladed crystal habit and variable hardness. Commonly found in Brazil, Nepal, Switzerland, and the United States (North Carolina/Virginia). Collectors should look for long, pearly, blue 'blades'.