igneous
Granite pebble
Granite; chiefly quartz, feldspar, and mica/amphibole
AI-generated identification · may be incorrectCoarse-grained, mottled white-gray rock with visible interlocking crystals; quartz hardness 7, feldspar 6–6.5, low-to-moderate vitreous luster, no cleavage as a whole, and specific gravity about 2.6–2.7.
Identified More igneous →
Explore Granite pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse-grained, mottled white-gray rock with visible interlocking crystals; quartz hardness 7, feldspar 6–6.5, low-to-moderate vitreous luster, no cleavage as a whole, and specific gravity about 2.6–2.7.
Formation & geological history
Intrusive igneous rock formed by slow cooling of silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic mountain-building; this rounded specimen was likely weathered and transported in a stream or glacial deposit.
Uses & applications
Used widely as crushed aggregate, building stone, countertops, monuments, and landscaping material; this small pebble has negligible commercial value.
Geological facts
The pale crystals are likely feldspar and quartz, while darker grains may be biotite or amphibole. Its rounded shape reflects abrasion during transport.
Field identification & locations
Identify it by its speckled, interlocking crystals and inability to split into layers; a glassy quartz grain can scratch glass, while feldspar commonly shows cleavage. Common worldwide in continental crust and gravel beds.
