igneous
Pegmatitic granite
Coarse-grained granitic rock, chiefly quartz, feldspar, and mica; locally possible garnet or tourmaline
AI-generated identification · may be incorrectHardness about 6–7 Mohs; mottled cream, pink, brown, gray, and black, with a granular crystalline texture and vitreous-to-pearly luster. Quartz is noncleaving, feldspar shows two cleavages, and mica occurs in platy flakes.
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Physical properties
Hardness about 6–7 Mohs; mottled cream, pink, brown, gray, and black, with a granular crystalline texture and vitreous-to-pearly luster. Quartz is noncleaving, feldspar shows two cleavages, and mica occurs in platy flakes.
Formation & geological history
Formed when silica-rich magma crystallized slowly, commonly in a late-stage pegmatite vein or granitic intrusion. Such rocks are generally Precambrian to Phanerozoic, depending on locality; age cannot be determined from the image.
Uses & applications
Used as decorative stone, aggregate, and occasionally as a lapidary specimen; attractive feldspar, quartz, garnet, or tourmaline zones may have collector value.
Geological facts
The unusually large, interlocking crystals suggest pegmatitic growth rather than ordinary granite, though the surface appears weathered and partly rounded.
Field identification & locations
Identify it by visible quartz, pale feldspar, dark mica, and coarse interlocking grains; common in continental mountain belts and granite/pegmatite terrains. A locality label and fresh broken surface would improve identification.
