igneous
Weathered granitic rock
Granitoid, likely biotite granite or granodiorite
AI-generated identification · may be incorrectCoarse-grained, mottled gray-green and tan specimen with visible quartz, feldspar, and dark mica; typically Mohs 6–7, vitreous to dull luster, interlocking crystals, and poor cleavage as a whole rock.
Identified More igneous →
Explore Weathered granitic rock in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse-grained, mottled gray-green and tan specimen with visible quartz, feldspar, and dark mica; typically Mohs 6–7, vitreous to dull luster, interlocking crystals, and poor cleavage as a whole rock.
Formation & geological history
Formed when silica-rich magma slowly crystallized deep in the continental crust, commonly during Precambrian or Phanerozoic plutonic events; its rounded surface reflects weathering and abrasion.
Uses & applications
Used as crushed aggregate, building stone, monuments, and decorative material; this small weathered piece has negligible commercial value.
Geological facts
The greenish appearance may result from chlorite replacing biotite or from surface weathering. Granitoids commonly contain quartz, potassium feldspar, plagioclase, and accessory mica or amphibole.
Field identification & locations
Look for coarse interlocking crystals, pale feldspar, glassy gray quartz, and scattered dark mica; granite and granodiorite are widespread in continental mountain belts and exposed shields. A fresh broken surface would improve identification.
