igneous
Weathered granite cobble
Granite, a coarse-grained felsic intrusive igneous rock
AI-generated identification · may be incorrectBrown, rounded, rough surface with visible light and dark mineral grains; likely quartz, feldspar, and biotite or other dark minerals. Typical granite hardness is about 6–7 Mohs, with a granular texture and no consistent cleavage as a whole rock; the brown color likely reflects surface weathering and iron staining.
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Physical properties
Brown, rounded, rough surface with visible light and dark mineral grains; likely quartz, feldspar, and biotite or other dark minerals. Typical granite hardness is about 6–7 Mohs, with a granular texture and no consistent cleavage as a whole rock; the brown color likely reflects surface weathering and iron staining.
Formation & geological history
Formed when silica-rich magma cooled slowly underground, allowing crystals to grow. Its age cannot be determined from the image; granite ranges widely in geological age and commonly occurs in continental crust, later rounded by erosion and transport.
Uses & applications
Granite is widely used as building and paving stone, aggregate, monuments, and countertops; this rounded specimen is mainly suitable for collecting or decoration.
Geological facts
Granite is a rock composed of interlocking minerals rather than a single mineral. The rounded shape and rusty-brown weathering rind suggest prolonged exposure or transport, but do not establish its source.
Field identification & locations
Look for visible interlocking quartz and feldspar grains, often with dark mica; a fresh broken surface would be more diagnostic than this weathered exterior. Granite is common in continental mountain belts and glacial or river deposits; the exact location cannot be identified from the image.
