igneous
Granite or granitic rock fragment
Granite, primarily quartz, feldspar, and mica; exact identification is uncertain from the photograph
AI-generated identification · may be incorrectCoarse, speckled white-gray appearance with dark biotite/amphibole; likely Mohs hardness 6–7, vitreous to dull luster, interlocking crystalline texture, and no obvious cleavage as a whole rock. The rounded shape suggests abrasion or tumbling.
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Physical properties
Coarse, speckled white-gray appearance with dark biotite/amphibole; likely Mohs hardness 6–7, vitreous to dull luster, interlocking crystalline texture, and no obvious cleavage as a whole rock. The rounded shape suggests abrasion or tumbling.
Formation & geological history
Forms when silica-rich magma slowly crystallizes deep within continental crust, commonly during Precambrian to Phanerozoic mountain-building events; the specimen was later weathered and rounded.
Uses & applications
Used extensively as building stone, countertops, monuments, aggregate, and landscaping material; small ordinary fragments generally have no jewelry value.
Geological facts
Granite is defined by abundant quartz and alkali feldspar, though similar-looking granodiorite or gneiss can be difficult to distinguish visually. A hand lens should reveal individual translucent quartz grains and blocky feldspar.
Field identification & locations
Common worldwide, especially in continental shields and mountain belts; major sources include India, Brazil, Scandinavia, Canada, and the United States. Confirm with a fresh surface, streak testing, and mineral identification rather than color alone.
