mineral

Blue mineral specimen, likely kyanite

Kyanite — Al₂SiO₅

AI-generated identification · may be incorrect

Usually blue, with a vitreous to pearly luster and bladed crystals; hardness is strongly directional, about 4.5–5 parallel to blades and 6.5–7 across them. The specimen appears rough and blue, but the photo does not confirm crystal form or composition.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Kyanite forms during regional metamorphism of aluminum-rich sedimentary rocks, commonly schist and gneiss, at moderate-to-high pressure. It is generally associated with metamorphic rocks of varied ages rather than a single geological period.

Uses & applications

Used as a refractory and ceramic raw material; attractive transparent or well-formed blue crystals are collected and sometimes cut as gemstones. Similar-looking blue minerals include celestine, fluorite, calcite, and blue quartz.

Geological facts

Kyanite is a polymorph of andalusite and sillimanite: all share Al₂SiO₅ chemistry but form under different pressure-temperature conditions.

Field identification & locations

Look for elongated blue blades, directional hardness, and cleavage; common localities include Nepal, Switzerland, Brazil, the United States, and India. Confirmation requires hardness testing, cleavage examination, or laboratory analysis.