igneous
Weathered mica-rich pegmatite
Granitic pegmatite composed chiefly of quartz, feldspar, and mica (likely biotite/muscovite)
AI-generated identification · may be incorrectCoarse, irregular interlocking crystals with brown-gold iron staining, dark platy mica, and pale quartz/feldspar. Quartz and feldspar are about Mohs 6–7; mica is about 2–3 and splits into sheets; luster ranges from glassy to pearly.
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Physical properties
Coarse, irregular interlocking crystals with brown-gold iron staining, dark platy mica, and pale quartz/feldspar. Quartz and feldspar are about Mohs 6–7; mica is about 2–3 and splits into sheets; luster ranges from glassy to pearly.
Formation & geological history
Likely formed as a slowly cooled, silica-rich intrusion or late-stage granitic vein, allowing large crystals to grow; the image alone cannot establish its age or exact origin. Rust-colored surfaces likely reflect weathering of iron-bearing minerals.
Uses & applications
Pegmatite may yield feldspar, quartz, mica, and occasionally gemstones or rare metals; this small rough specimen is mainly suitable for collecting or display.
Geological facts
Pegmatites can contain exceptionally large crystals and economically important minerals, although none can be confirmed from this specimen alone.
Field identification & locations
Look for unusually coarse interlocking grains, glassy pale quartz, feldspar, and flaky mica. Pegmatites occur in granitic terrains worldwide; mineral identification would require closer examination or testing.
