mineral
Blue kyanite
Kyanite (Al₂SiO₅)
AI-generated identification · may be incorrectTypically bladed, blue crystals with vitreous to pearly luster and perfect cleavage; Mohs hardness varies by direction, about 4.5–5 parallel to the blades and 6.5–7 across them. The specimen appears pale blue and elongated, consistent with kyanite.
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Physical properties
Typically bladed, blue crystals with vitreous to pearly luster and perfect cleavage; Mohs hardness varies by direction, about 4.5–5 parallel to the blades and 6.5–7 across them. The specimen appears pale blue and elongated, consistent with kyanite.
Formation & geological history
Forms during regional metamorphism of aluminum-rich rocks, commonly in schist and gneiss; age depends on its host rock and can range from ancient to geologically recent. Its distinctive hardness variation reflects its anisotropic crystal structure.
Uses & applications
Used as a high-temperature refractory material and collected as a mineral; transparent, well-formed crystals are occasionally cut as gemstones.
Geological facts
Kyanite’s hardness differs markedly depending on the direction tested, a useful diagnostic property.
Field identification & locations
Look for flat, bladed blue crystals, often with lengthwise striations, in metamorphic rocks. Common localities include Brazil, Nepal, India, and the eastern United States.
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Metamorphic
Sandstone (with potential mineral staining/concretions)
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Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
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Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Granite
Granite (Phaneritic intrusive igneous rock)
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