![Pegmatite with muscovite mica (Granitic pegmatite; chiefly quartz (SiO₂), feldspar, and muscovite mica [KAl₂(AlSi₃O₁₀)(OH)₂]) — igneous](https://media.rock.id/pegmatite-with-muscovite-mica-ce5d8d13-f6c8-49c1-b293-c8908bf0f774-compressed.jpg)
igneous
Pegmatite with muscovite mica
Granitic pegmatite; chiefly quartz (SiO₂), feldspar, and muscovite mica [KAl₂(AlSi₃O₁₀)(OH)₂]
AI-generated identification · may be incorrectCoarse, interlocking crystals with silvery reflective mica, pale quartz, and pinkish feldspar; vitreous to pearly luster. Quartz hardness 7, feldspar 6–6.5, muscovite 2–2.5; mica shows perfect basal cleavage, while quartz has none.
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Physical properties
Coarse, interlocking crystals with silvery reflective mica, pale quartz, and pinkish feldspar; vitreous to pearly luster. Quartz hardness 7, feldspar 6–6.5, muscovite 2–2.5; mica shows perfect basal cleavage, while quartz has none.
Formation & geological history
Formed when water-rich granitic magma cooled slowly in late-stage veins, allowing exceptionally large crystals to grow, typically during Precambrian–Phanerozoic intrusive events.
Uses & applications
Used as a source of feldspar, quartz, and mica for ceramics, glass, electrical insulation, and fillers; attractive pieces are collected as mineral specimens.
Geological facts
The bright flaky reflections are characteristic of muscovite, commonly called “mica.” Pegmatites can also host tourmaline, beryl, garnet, and lithium minerals.
Field identification & locations
Identify by visible large crystals, flaky elastic mica sheets, glassy quartz, and blocky feldspar; common in granitic terrains worldwide, including Brazil, the United States, Madagascar, and Scandinavia.
