igneous
Weathered granite
Granite, chiefly quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, brown-and-white rock with visible interlocking crystals; likely Mohs 6–7, vitreous to pearly luster, no consistent cleavage as a whole, and specific gravity about 2.6–2.7. White areas are probably feldspar or quartz, while dark flecks are biotite or amphibole; surface staining reflects weathering.
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Physical properties
Coarse-grained, brown-and-white rock with visible interlocking crystals; likely Mohs 6–7, vitreous to pearly luster, no consistent cleavage as a whole, and specific gravity about 2.6–2.7. White areas are probably feldspar or quartz, while dark flecks are biotite or amphibole; surface staining reflects weathering.
Formation & geological history
Granite forms when silica-rich magma cools slowly deep within continental crust, allowing large crystals to grow. Most exposed granite bodies formed during Precambrian to Phanerozoic orogenies and were later uplifted and weathered.
Uses & applications
Used as dimension stone, countertops, monuments, building aggregate, and landscaping material; ordinary hand specimens have minimal commercial value.
Geological facts
The image shows a weathered, iron-stained specimen, but exact identification would require a fresh surface or tests. Quartz is typically glassy and harder than a steel knife, whereas feldspar commonly shows flat cleavage faces.
Field identification & locations
Common in continental mountain belts and exposed basement terrains worldwide. Look for interlocking quartz, feldspar, and dark mica grains; fizzing with dilute acid is generally absent.
