igneous
Weathered granite or granitic gneiss
Granite; primarily quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse, light gray to pinkish-gray, granular texture with visible interlocking mineral grains; typically Mohs 6–7, vitreous quartz luster, no obvious cleavage as a whole, and specific gravity about 2.6–2.7. The photo is insufficient to distinguish unambiguously between granite and gneiss.
Identified More igneous →
Explore Weathered granite or granitic gneiss in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse, light gray to pinkish-gray, granular texture with visible interlocking mineral grains; typically Mohs 6–7, vitreous quartz luster, no obvious cleavage as a whole, and specific gravity about 2.6–2.7. The photo is insufficient to distinguish unambiguously between granite and gneiss.
Formation & geological history
Granite forms when silica-rich magma slowly crystallizes deep underground, generally during Precambrian to Phanerozoic crustal episodes; gneiss is metamorphosed granite. Weathering has rounded and roughened this specimen.
Uses & applications
Used widely as building stone, aggregate, curbing, monuments, countertops, and crushed-rock landscaping material; this ordinary fragment has little jewelry or collector value.
Geological facts
The speckled appearance reflects large interlocking feldspar and quartz grains that cooled slowly. Dark patches may be biotite or amphibole, while reddish areas commonly indicate iron-stained feldspar.
Field identification & locations
Look for visible quartz, white or pink feldspar, and black mica in a crystalline, nonlayered texture; distinct banding would favor gneiss. Common worldwide, especially in exposed mountain and continental-crust terrains.
