igneous
Likely weathered granite or granitic gneiss fragments
Granite: quartz–feldspar–mica aggregate; possibly biotite granite or weakly foliated gneiss
AI-generated identification · may be incorrectGray-brown, granular, dull to weakly sparkling surfaces with visible quartz/feldspar and dark mica; typically Mohs 6–7, no consistent cleavage as a whole rock, and specific gravity about 2.63–2.75.
Identified More igneous →
Explore Likely weathered granite or granitic gneiss fragments in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray-brown, granular, dull to weakly sparkling surfaces with visible quartz/feldspar and dark mica; typically Mohs 6–7, no consistent cleavage as a whole rock, and specific gravity about 2.63–2.75.
Formation & geological history
Formed from slowly cooled silica-rich magma deep in the crust, generally Precambrian to Mesozoic depending on locality; fragments may be weathered or mechanically broken. The image alone cannot establish a precise age or composition.
Uses & applications
Commonly used as building stone, aggregate, countertops, monuments, and landscaping rock; ordinary hand specimens have little commercial value.
Geological facts
Granite’s interlocking crystals distinguish it from many sedimentary rocks; gneiss may show subtle mineral banding or foliation caused by metamorphism.
Field identification & locations
Look for interlocking light quartz/feldspar grains and scattered black mica; a glassy quartz grain can scratch glass, while a steel nail usually will not scratch fresh surfaces. Common worldwide, especially in continental shields and mountain belts.
