igneous
Granite
Granite; chiefly quartz (SiO₂), feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, speckled gray-and-white rock with interlocking crystals; quartz and feldspar give a glassy to pearly luster, while mica may appear dark and reflective. Hardness is typically 6–7 Mohs; no cleavage as a whole, though individual minerals have cleavage; density about 2.63–2.75 g/cm³.
Identified More igneous →
Explore Granite 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 interlocking crystals; quartz and feldspar give a glassy to pearly luster, while mica may appear dark and reflective. Hardness is typically 6–7 Mohs; no cleavage as a whole, though individual minerals have cleavage; density about 2.63–2.75 g/cm³.
Formation & geological history
An intrusive igneous rock formed when silica-rich magma cooled slowly deep underground, allowing large crystals to grow, commonly during Precambrian to Phanerozoic mountain-building events.
Uses & applications
Widely used for countertops, monuments, building stone, paving, and crushed aggregate; attractive pieces are collected but usually have modest value.
Geological facts
Its visible crystals indicate slow subterranean cooling. The exact specimen may instead be granodiorite or a related coarse-grained granitoid, which can look nearly identical in a photograph.
Field identification & locations
Identify it by coarse interlocking quartz, white or pink feldspar, and black mica or amphibole; it is common in continental crust and mountain belts worldwide. A glassy scratch-resistant quartz grain and lack of layering help distinguish it from sandstone or gneiss.
