igneous
Pegmatite
Granitic pegmatite, chiefly quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, with interlocking pale quartz, pinkish feldspar, and dark mica; individual minerals are typically Mohs 2–7, with vitreous quartz and pearly-to-vitreous feldspar. The photo’s visible pink and white crystals and mica-like dark flakes are consistent with pegmatite, though exact mineral identification requi…
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Physical properties
Coarse-grained, with interlocking pale quartz, pinkish feldspar, and dark mica; individual minerals are typically Mohs 2–7, with vitreous quartz and pearly-to-vitreous feldspar. The photo’s visible pink and white crystals and mica-like dark flakes are consistent with pegmatite, though exact mineral identification requires testing.
Formation & geological history
Crystallized from water-rich residual magma, commonly in veins and dikes associated with granite; pegmatites formed throughout geologic time, often during late stages of granite emplacement.
Uses & applications
Pegmatite is collected as a specimen and may host valuable minerals and gemstones; its quartz and feldspar can also be used in glass and ceramics.
Geological facts
Pegmatites can contain exceptionally large crystals and economically important lithium, tantalum, and beryllium minerals.
Field identification & locations
Look for very coarse interlocking crystals, commonly quartz, feldspar, and mica, in granitic settings; common in pegmatite districts worldwide. The pictured specimen appears pegmatitic, but a photo cannot confirm its composition.
