igneous
Weathered granitic rock
Granite or granodiorite, likely quartz–feldspar–mica aggregate
AI-generated identification · may be incorrectHardness about 6–7 Mohs; coarse, irregular granular texture with pale gray-green feldspar/quartz and brown iron-oxide staining. Nonmetallic to dull luster, no obvious cleavage as a whole, and typical specific gravity around 2.6–2.8.
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Physical properties
Hardness about 6–7 Mohs; coarse, irregular granular texture with pale gray-green feldspar/quartz and brown iron-oxide staining. Nonmetallic to dull luster, no obvious cleavage as a whole, and typical specific gravity around 2.6–2.8.
Formation & geological history
A plutonic igneous rock crystallized slowly from magma deep in the crust, generally during Precambrian or younger continental crust formation; surface weathering produced the rusty brown coating.
Uses & applications
Used as crushed aggregate, dimension stone, paving, and building material; this small weathered piece has little jewelry or commercial value.
Geological facts
The visible greenish and brown colors may reflect altered chlorite/epidote-bearing minerals and oxidation of biotite or other iron-bearing minerals rather than a distinct gemstone.
Field identification & locations
Look for interlocking visible grains of quartz and feldspar, scattered dark mica, and a hard unfoliated texture. Common worldwide in continental mountain belts and exposed batholiths; a fresh broken surface would improve identification.
