mineral

Blue Kyanite

Kyanite (Al2SiO5)

Hardness: Variable (4.5 parallel to the long axis and 6.5–7.0 perpendicular to it); Color: Blue, often with white streaks or zoning; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect; Specific gravity: 3.53–3.67

Hardness: Variable (4
Color: Blue, often with white streaks or zoning
Luster: Vitreous to pearly

Identified March 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed through high-pressure regional metamorphism of clay-rich sedimentary rocks. It is a common indicator of high-pressure metamorphic environments. Age varies based on the host rock, found in Precambrian to Cenozoic formations.

Uses & applications

Used industrially in the manufacture of refractory products like porcelain, ceramics, and brake pads due to its high heat resistance. It is also used in jewelry (cabochons or faceted stones) and for metaphysical collecting.

Geological facts

Kyanite is one of the few minerals that exhibits anisotropic hardness, meaning its hardness changes drastically depending on which direction you scratch it. Its name is derived from the Greek word 'kyanos', meaning blue.

Field identification & locations

Identify in the field by its distinct bladed crystal habit, pearly luster, and the varying hardness test. Commonly found in metamorphic schist and gneiss. Major localities include Brazil, Switzerland, Russia, and the USA (North Carolina).