Mineral

Kyanite

Kyanite (Al2SiO5)

Hardness: 4.5 to 7 Mohs (variable by axis); Color: Blue, ranging from light to deep indigo, often with white or gray streaking; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in one direction; Specific gravity: 3.53 - 3.67.

Hardness: 4
Luster: Vitreous to pearly

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the high-pressure regional metamorphism of clay-rich sedimentary rocks. It is most commonly found in metamorphic gneisses, schists, and pegmatites. It is an index mineral used to estimate the depth and pressure of metamorphic events.

Uses & applications

Industrially used to manufacture refractory products like porcelain, ceramics, and kiln bricks due to its heat resistance. In jewelry, it is used for beads, cabochons, and occasionally faceted gems. It is also a very popular specimen for crystal healing and mineral collectors.

Geological facts

Kyanite is unusual because its hardness varies significantly depending on the direction of the cut. It is hard (7) when tested across the crystals and softer (4.5) when tested parallel to the long axis. This property is known as anisotropy.

Field identification & locations

Identify in the field by its distinct bladed crystal habit and blue color. It is commonly found in Brazil, Nepal, Switzerland, and the USA (North Carolina and Georgia). It does not accumulate negative energy and never requires 'cleansing' in metaphysical circles.