igneous
Granite pebble
Granite, typically quartz–feldspar–mica aggregate
AI-generated identification · may be incorrectMedium- to coarse-grained, mottled white/gray with dark biotite or amphibole; vitreous quartz and feldspar luster, massive texture, no cleavage as a whole. Hardness about 6–7 Mohs; specific gravity roughly 2.63–2.75.
Identified More igneous →
Explore Granite pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Medium- to coarse-grained, mottled white/gray with dark biotite or amphibole; vitreous quartz and feldspar luster, massive texture, no cleavage as a whole. Hardness about 6–7 Mohs; specific gravity roughly 2.63–2.75.
Formation & geological history
Intrusive felsic igneous rock formed by slow cooling of silica-rich magma deep in the continental crust, commonly during Precambrian to Phanerozoic mountain-building. This rounded specimen was likely transported and abraded by a river, beach, or glacial process.
Uses & applications
Widely used as crushed aggregate, building stone, countertops, monuments, paving, and landscaping; small rounded pieces are inexpensive geological specimens.
Geological facts
The speckled appearance reflects interlocking quartz, potassium feldspar, plagioclase, and dark mica or amphibole crystals. Exact identification is limited by the small, weathered image and could include a closely related granitic rock such as granodiorite.
Field identification & locations
Look for visible interlocking crystals, abundant pale feldspar/quartz, and scattered dark minerals; it should not fizz with dilute hydrochloric acid. Common worldwide in continental shields and mountain belts.
