igneous
Weathered granite or granitic gneiss fragments
Granite; chiefly quartz, feldspar, and biotite/hornblende
AI-generated identification · may be incorrectCoarse, mottled cream, gray, brown, and black grains with crystalline texture and uneven fracture; quartz is Mohs 7, feldspar about 6, and overall specific gravity roughly 2.6–2.7. The rounded edges and dark surface staining indicate weathering or abrasion.
Identified More igneous →
Explore Weathered granite or granitic gneiss fragments in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Coarse, mottled cream, gray, brown, and black grains with crystalline texture and uneven fracture; quartz is Mohs 7, feldspar about 6, and overall specific gravity roughly 2.6–2.7. The rounded edges and dark surface staining indicate weathering or abrasion.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in continental crust, commonly during Precambrian to Phanerozoic mountain-building events; the pieces may be eroded, transported, and weathered surface debris.
Uses & applications
Used extensively as dimension stone, countertops, monuments, aggregate, and decorative landscaping rock; small ordinary fragments have little jewelry use.
Geological facts
Granite is identified by visible interlocking light quartz/feldspar grains plus darker mica or amphibole, unlike many sedimentary rocks. Strong weathering can produce rusty-brown iron-oxide coatings.
Field identification & locations
Common worldwide, especially in continental shields and mountain belts. Test for visible quartz and feldspar grains, lack of layering, and hardness sufficient to scratch glass; a hand lens and streak test help distinguish it from iron-rich slag.
