mineral

Green Kyanite

Kyanite (Al2SiO5)

Hardness: variable 4.5-5.0 along axes and 6.5-7.0 across axes (Mohs scale). Color: pale to lime green. Luster: Vitreous to pearly. Crystal structure: Triclinic. Cleavage: Perfect in one direction.

Hardness: variable 4
Color: pale to lime green
Luster: Vitreous to pearly

Identified March 15, 2026More mineral →

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Physical properties

Hardness: variable 4.5-5.0 along axes and 6.5-7.0 across axes (Mohs scale). Color: pale to lime green. Luster: Vitreous to pearly. Crystal structure: Triclinic. Cleavage: Perfect in one direction.

Formation & geological history

Formed during the regional metamorphism of clay-rich sedimentary rocks at high pressure. Green kyanite specifically often forms in environment rich in chromium or within certain pegmatites.

Uses & applications

Used primarily by mineral collectors and in metaphysical jewelry. Industrial kyanite (typically blue) is used to manufacture heat-resistant ceramics (mullite), spark plugs, and foundry molds.

Geological facts

Kyanite is one of the few minerals that exhibits a significant variation in hardness depending on the direction of the crystal (anisotropy). The green variety is much rarer than the common blue variety.

Field identification & locations

Identify in the field by its bladed, fibrous crystal habit and its unique variable hardness. Commonly found in Brazil, India, and certain locations in the Appalachian Mountains, USA.