igneous
Granite or granitic pebble
Granite; chiefly quartz (SiO₂), feldspar, and mica/amphibole
AI-generated identification · may be incorrectHardness about 6–7 Mohs; coarse-grained, speckled gray-green and black, with a vitreous-to-dull luster. Interlocking crystals and no obvious cleavage as a whole are typical.
Identified More igneous →
Explore Granite or granitic pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness about 6–7 Mohs; coarse-grained, speckled gray-green and black, with a vitreous-to-dull luster. Interlocking crystals and no obvious cleavage as a whole are typical.
Formation & geological history
An intrusive igneous rock formed by slow cooling of silica-rich magma deep underground, generally in Precambrian to Phanerozoic continental crust. The specimen is likely a weathered glacial or stream-rounded fragment.
Uses & applications
Widely used as dimension stone, countertops, paving, monuments, aggregate, and landscaping material; ordinary pebbles have little commercial value.
Geological facts
The image is somewhat blurred, so exact identification is uncertain; the texture could also represent a dark metamorphic rock such as gneiss or amphibolite.
Field identification & locations
Look for visible interlocking grains of light feldspar/quartz and dark biotite or amphibole; a glassy black streak or strong foliation would suggest another rock. Common worldwide, especially in continental mountain belts and glacial deposits.
