igneous
Weathered granite or granitic gneiss
Granite: quartz + feldspar + mica; possible gneissic variant
AI-generated identification · may be incorrectCoarse, unevenly interlocking grains with pale feldspar/quartz and dark biotite or hornblende; typically Mohs 6–7, vitreous to dull luster, no prominent cleavage as a whole, and specific gravity about 2.63–2.75.
Identified More igneous →
Explore Weathered granite or granitic gneiss in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse, unevenly interlocking grains with pale feldspar/quartz and dark biotite or hornblende; typically Mohs 6–7, vitreous to dull luster, no prominent cleavage as a whole, and specific gravity about 2.63–2.75.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic mountain-building; surface weathering rounded this specimen. The image may also show weak metamorphic banding, suggesting granitic gneiss.
Uses & applications
Widely used as dimension stone, countertops, monuments, crushed aggregate, and landscaping rock; attractive polished pieces are collected but usually have modest value.
Geological facts
The dark minerals are likely biotite or amphibole, while the orange-brown areas are iron-oxide weathering products. Granite is a major component of continental crust.
Field identification & locations
Identify it by visible quartz, blocky feldspar, dark mica/amphibole, coarse grain size, and hardness sufficient to scratch glass. Common worldwide, especially in exposed continental shields and mountain belts.
