mineral

Black Kyanite

Kyanite (Al2SiO5) with carbonaceous inclusions

Hardness: 4.5-7 (variable along axes); Color: Black or dark grey; Luster: Vitreous to pearly; Crystal structure: Triclinic (bladed); Cleavage: Perfect; Gravity: 3.53–3.67.

Hardness: 4
Color: Black or dark grey
Luster: Vitreous to pearly

Identified May 10, 2026More mineral →

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Physical properties

Hardness: 4.5-7 (variable along axes); Color: Black or dark grey; Luster: Vitreous to pearly; Crystal structure: Triclinic (bladed); Cleavage: Perfect; Gravity: 3.53–3.67.

Formation & geological history

Forms during high-pressure regional metamorphism of clay-rich sedimentary rocks. The black color is typically caused by inclusions of carbonaceous matter or graphite. Found in metamorphic schist and gneiss.

Uses & applications

Primarily used as a collector specimen and in metaphysical practices. Industrial kyanite is used for high-heat refractory products like furnace linings and spark plugs.

Geological facts

Black Kyanite is famous for its fan-like or bladed 'broomstick' formations. It is one of the few minerals that exhibits two different hardnesses depending on which direction the crystal is scratched.

Field identification & locations

Identified by its distinctive bladed crystal habit and fan shape. Commonly found in Brazil, India, and parts of the United States like North Carolina and Georgia. Watch for the 'splintery' appearance of the blades.

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