igneous
Polished granite pebble
Granite, a quartz–feldspar plutonic rock
AI-generated identification · may be incorrectCoarse-grained, speckled pink, white, and black; composed mainly of quartz, feldspars, and mica or amphibole. Individual minerals have Mohs hardnesses of about 2–7; granite has no consistent cleavage and a granular texture. The rounded pebble appears naturally water-worn and possibly polished.
Identified More igneous →
Explore Polished granite pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse-grained, speckled pink, white, and black; composed mainly of quartz, feldspars, and mica or amphibole. Individual minerals have Mohs hardnesses of about 2–7; granite has no consistent cleavage and a granular texture. The rounded pebble appears naturally water-worn and possibly polished.
Formation & geological history
Granite forms when silica-rich magma cools slowly underground, commonly within continental crust; its age varies widely, from Precambrian to recent geological periods. The pebble was later rounded by transport in water or sediment.
Uses & applications
Granite is widely used for countertops, building stone, paving, and monuments; small polished pieces are collected or used decoratively.
Geological facts
Its visible grains are interlocking crystals, typically including hard, glassy quartz and pink or white feldspar.
Field identification & locations
Look for a coarse, interlocking mix of light quartz/feldspar and dark minerals; unlike a single-mineral rock, granite shows several distinct grains. Granites occur worldwide, and pebbles are common in river and beach gravels.
