igneous
Granite pebble
Granite; chiefly quartz (SiO₂), feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, speckled gray-and-white rock with black mica/hornblende; minerals show a granular texture and vitreous to pearly luster. Hardness is roughly 6–7 Mohs; no consistent cleavage as a whole; density about 2.6–2.7 g/cm³.
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, speckled gray-and-white rock with black mica/hornblende; minerals show a granular texture and vitreous to pearly luster. Hardness is roughly 6–7 Mohs; no consistent cleavage as a whole; density about 2.6–2.7 g/cm³.
Formation & geological history
Intrusive igneous rock crystallized slowly from silica-rich magma deep in Earth’s crust, commonly during Precambrian to Phanerozoic plutonic events. The rounded specimen was likely produced by weathering and transport.
Uses & applications
Widely used for countertops, monuments, building stone, road aggregate, and landscaping; this small pebble has little commercial value.
Geological facts
The visible black grains are likely biotite or amphibole, while the light grains are feldspar and quartz. Granite’s interlocking crystals reflect slow underground cooling.
Field identification & locations
Identify it by its coarse interlocking crystals, mottled appearance, and inability to scratch easily with a steel nail. Common worldwide in continental crust and glacial or stream gravels.
