igneous
Granite or granitic gneiss
Quartz–feldspar–mica granitoid; possibly foliated gneiss
AI-generated identification · may be incorrectCoarse-grained, light gray rock with visible white feldspar, translucent gray quartz, and darker mica/amphibole; typically Mohs 6–7, vitreous to pearly luster, interlocking crystals, and no obvious cleavage as a whole rock.
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Physical properties
Coarse-grained, light gray rock with visible white feldspar, translucent gray quartz, and darker mica/amphibole; typically Mohs 6–7, vitreous to pearly luster, interlocking crystals, and no obvious cleavage as a whole rock.
Formation & geological history
Likely crystallized slowly from silica-rich magma deep in the crust, commonly Precambrian to Paleozoic in age; if foliation is genuine, later metamorphism produced granitic gneiss.
Uses & applications
Used as crushed stone, aggregate, building stone, countertops, monuments, and landscaping material; this rounded hand specimen has little commercial value.
Geological facts
The granular “salt-and-pepper” texture and pale quartz-feldspar composition distinguish it from most volcanic rocks; weathering commonly rounds exposed pieces.
Field identification & locations
Look for interlocking visible crystals, abundant quartz and feldspar, and hardness sufficient to scratch glass. Common worldwide, especially in continental shields and mountain belts; a definitive identification may require a fresh break or thin section.
