mineral
Blue Kyanite
Kyanite (Al2SiO5)
Hardness: 4.5 to 5.0 (perpendicular to length) and 6.5 to 7.0 (parallel to length). Color: Blue, white, gray. Luster: Vitreous to pearly. Crystal structure: Triclinic. Cleavage: Perfect in one direction.
- Hardness
- 4
- Color
- Blue, white, gray
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 4.5 to 5.0 (perpendicular to length) and 6.5 to 7.0 (parallel to length). Color: Blue, white, gray. Luster: Vitreous to pearly. Crystal structure: Triclinic. Cleavage: Perfect in one direction.
Formation & geological history
Formed during regional metamorphism of clay-rich sedimentary rocks (pelites) under high pressure. Commonly found in metamorphic rocks like schist and gneiss.
Uses & applications
Industrial uses include high-resistance ceramics (spark plugs), refractory products, and abrasives. Also used in jewelry as cabochons and for metaphysical purposes.
Geological facts
Kyanite is an aluminosilicate polymorph, sharing the same chemistry as Andalusite and Sillimanite but forming under different temperature-pressure conditions. It is one of the few minerals that has a significantly varying hardness depending on the direction of the scratch.
Field identification & locations
Identify by its bladed crystal habit, distinct blue color, and anisotropic hardness. Common locations include Brazil, USA (North Carolina), Switzerland, and Nepal.
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Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock
Granite
Granite (Phaneritic intrusive igneous rock)
igneous