igneous
Pegmatitic granite
Coarse-grained granite, likely quartz–alkali feldspar–biotite pegmatite
AI-generated identification · may be incorrectHardness about 6–7 Mohs; pink to salmon feldspar, translucent gray-white quartz, and dark mica or iron-stained minerals. It has a coarse interlocking crystalline texture, vitreous quartz luster, and feldspar cleavage; specific gravity is typically 2.6–2.7.
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Physical properties
Hardness about 6–7 Mohs; pink to salmon feldspar, translucent gray-white quartz, and dark mica or iron-stained minerals. It has a coarse interlocking crystalline texture, vitreous quartz luster, and feldspar cleavage; specific gravity is typically 2.6–2.7.
Formation & geological history
Formed when silica-rich magma crystallized slowly, commonly in a late-stage pegmatite vein or granite body. Such rocks are generally Precambrian to younger, depending on the locality.
Uses & applications
Used as decorative stone, countertops, aggregate, and architectural material; attractive feldspar–quartz pieces are collected, though this specimen appears common-grade.
Geological facts
The unusually large crystals reflect slow cooling and concentration of water-rich residual magma. Red-brown coloration commonly results from iron oxidation or alteration of feldspar and mica.
Field identification & locations
Identify it by visible interlocking pink feldspar, glassy quartz, and dark mica, with no layering or vesicles; a hand lens and scratch test help confirm it. Common in granite terrains and pegmatite districts worldwide.
