igneous
Coarse-grained granite
Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/muscovite mica
AI-generated identification · may be incorrectHardness is roughly 6–7 Mohs; the specimen is light gray to pinkish with visible glassy quartz, pale feldspar, and dark mica. It has a phaneritic, interlocking crystalline texture, generally no cleavage as a whole, and specific gravity around 2.63–2.75.
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Physical properties
Hardness is roughly 6–7 Mohs; the specimen is light gray to pinkish with visible glassy quartz, pale feldspar, and dark mica. It has a phaneritic, interlocking crystalline texture, generally no cleavage as a whole, and specific gravity around 2.63–2.75.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in continental crust, commonly during Precambrian to Phanerozoic intrusive events. Its exposed surface may also show weathering or alteration.
Uses & applications
Used extensively as dimension stone, countertops, monuments, paving, aggregate, and occasionally as decorative material. Attractive polished pieces are collected but usually have modest value.
Geological facts
The large visible crystals indicate slow underground cooling rather than volcanic eruption. Pink coloration commonly reflects potassium-rich feldspar, while black flakes are biotite or hornblende.
Field identification & locations
Identify it by its coarse, interlocking grains: translucent quartz, blocky feldspar, and dark mica, without layering or foliation. Common worldwide in continental mountain belts and exposed batholiths; a hand lens and streak-free glassy quartz help distinguish it from gneiss.
