igneous
Weathered quartz-bearing rock, likely granite or granitic gneiss
Feldspar–quartz–mica aggregate; probable granite (compositionally, quartz + feldspar + biotite/muscovite)
AI-generated identification · may be incorrectCoarse, speckled gray-white and brown material with vitreous quartz, dull/pearly feldspar, and dark mica or staining; likely Mohs hardness 6–7, no obvious cleavage as a whole, and moderate-to-high specific gravity around 2.6–2.8.
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Physical properties
Coarse, speckled gray-white and brown material with vitreous quartz, dull/pearly feldspar, and dark mica or staining; likely Mohs hardness 6–7, no obvious cleavage as a whole, and moderate-to-high specific gravity around 2.6–2.8.
Formation & geological history
Likely crystallized slowly from silica-rich magma deep underground, then exposed and weathered; if foliation is present, it may instead be metamorphic gneiss. Exact age and locality cannot be determined from the photograph.
Uses & applications
Common granite is used for crushed aggregate, building stone, monuments, countertops, and landscaping; ordinary hand specimens have little commercial value.
Geological facts
The rusty brown areas may be iron-oxide weathering, while the pale translucent grains are probably quartz. A fresh broken surface would better reveal whether the texture is igneous or metamorphic.
Field identification & locations
Identify it by interlocking visible grains of glassy quartz, light feldspar, and dark mica; granite lacks the strong layering typical of gneiss. Common worldwide, especially in continental crust and granitic mountain regions.
