igneous
Weathered quartz-rich granitic rock
Granite or granitic pegmatite; chiefly quartz (SiO₂), feldspar, and minor mica/iron oxides
AI-generated identification · may be incorrectHardness about 6–7 Mohs; pale gray to cream, granular, with vitreous quartz and dull feldspar, locally iron-stained. Massive crystalline texture and no obvious cleavage as a whole; the rounded shape reflects weathering and abrasion.
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Physical properties
Hardness about 6–7 Mohs; pale gray to cream, granular, with vitreous quartz and dull feldspar, locally iron-stained. Massive crystalline texture and no obvious cleavage as a whole; the rounded shape reflects weathering and abrasion.
Formation & geological history
An intrusive igneous rock crystallized slowly from silica-rich magma, commonly during Precambrian to Phanerozoic continental crust formation, then exposed and rounded by erosion. The exact specimen cannot be dated from the image.
Uses & applications
Used as crushed aggregate, building stone, countertops, monuments, and landscaping rock; attractive pieces are collected but generally have little gem value.
Geological facts
The visible orange-brown coloration is likely surface oxidation of iron-bearing minerals. The upper fragment appears to be a separate orange chalcedony or iron-stained quartz-rich specimen.
Field identification & locations
Identify by its coarse interlocking grains, visible glassy quartz, pale feldspar, and lack of layering or fossils; a hardness test and fresh broken surface help distinguish it from concrete. Common worldwide in continental shields, mountain belts, and granite terrains.
