igneous
Weathered granite or granitic gneiss
Granite; primarily quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse, mottled gray-brown rock with weathered feldspar, dark mica/amphibole, and possible quartz; Mohs hardness about 6–7, nonmetallic luster, interlocking crystals, and no prominent cleavage as a whole. The rounded shape and brown surface reflect outdoor weathering.
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Physical properties
Coarse, mottled gray-brown rock with weathered feldspar, dark mica/amphibole, and possible quartz; Mohs hardness about 6–7, nonmetallic luster, interlocking crystals, and no prominent cleavage as a whole. The rounded shape and brown surface reflect outdoor weathering.
Formation & geological history
Likely crystallized slowly from silica-rich magma deep in the continental crust, generally during Precambrian to younger continental magmatism; if foliation is confirmed, it may be granitic gneiss formed by later high-grade metamorphism.
Uses & applications
Granite is widely used as crushed stone, building stone, countertops, monuments, and paving; an ordinary hand specimen has little commercial value.
Geological facts
The image does not show diagnostic crystals clearly enough for a precise identification; it could also be a weathered metamorphic rock or coarse volcanic rock.
Field identification & locations
Look for visible quartz, pink/white feldspar, and black mica; acid testing is usually negative, while a steel nail generally will not scratch fresh surfaces. Common worldwide in continental uplands and exposed bedrock.
