igneous
Pegmatite with feldspar, quartz, and dark mica
Granitic pegmatite; commonly quartz (SiO₂), feldspar, and biotite or other mica
AI-generated identification · may be incorrectCoarse, unevenly grained specimen with pale feldspar/quartz and dark mica-like patches. Quartz has Mohs hardness 7; feldspar 6; mica typically 2–3, with vitreous to pearly luster and variable cleavage. Exact minerals cannot be confirmed from the photo alone.
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Physical properties
Coarse, unevenly grained specimen with pale feldspar/quartz and dark mica-like patches. Quartz has Mohs hardness 7; feldspar 6; mica typically 2–3, with vitreous to pearly luster and variable cleavage. Exact minerals cannot be confirmed from the photo alone.
Formation & geological history
Likely crystallized from silica-rich magma during the final stages of an intrusion, allowing large crystals to grow. Pegmatites formed throughout geologic time and commonly occur in veins or dikes cutting older rocks.
Uses & applications
Pegmatite is mined for feldspar, quartz, mica, and specialty minerals; attractive pieces are collected, while some pegmatite minerals are used in ceramics, glass, and electronics.
Geological facts
Pegmatites can host unusually large crystals and valuable minerals such as tourmaline, beryl, and lithium-bearing spodumene.
Field identification & locations
Look for coarse interlocking crystals and contrasting light quartz/feldspar with platy dark mica; common in granitic terrains worldwide. The pictured specimen is too small and weathered for confident mineral identification by sight alone.
