igneous
Rounded granitic pebble (likely granite or granodiorite)
Granite–granodiorite; chiefly quartz, feldspar, and mica/amphibole
AI-generated identification · may be incorrectCoarse crystalline, speckled gray, white, tan, and black grains with a dull to weakly vitreous luster; quartz hardness ~7, feldspar ~6, overall Mohs ~6–7. No obvious cleavage on the rounded surface; density typically 2.6–2.8 g/cm³.
Identified More igneous →
Explore Rounded granitic pebble (likely granite or granodiorite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse crystalline, speckled gray, white, tan, and black grains with a dull to weakly vitreous luster; quartz hardness ~7, feldspar ~6, overall Mohs ~6–7. No obvious cleavage on the rounded surface; density typically 2.6–2.8 g/cm³.
Formation & geological history
Slowly cooled silica-rich magma formed intrusive igneous rock, commonly during Precambrian–Phanerozoic mountain-building; its smooth shape results from stream or beach abrasion. Exact age and provenance require petrographic or geochemical testing.
Uses & applications
Used as aggregate, road stone, building stone, monuments, and landscaping material; attractive pieces may be polished as decorative specimens, but this rounded example has modest commercial value.
Geological facts
The visible interlocking crystals and mixed light/dark minerals distinguish it from homogeneous basalt or sedimentary pebbles. Brown coloration likely reflects iron-oxide weathering.
Field identification & locations
Identify by visible quartz and feldspar grains, granular texture, and lack of layering or foliation; common worldwide in glacial deposits, rivers, beaches, and areas exposing continental crust.
