igneous
Granite (likely weathered quartz-bearing granite)
Granite; primarily quartz, feldspar, and mica/amphibole
AI-generated identification · may be incorrectCoarse-grained, speckled white/gray rock with dark mineral flecks and rusty weathering; vitreous quartz and blocky feldspar, no obvious cleavage as a whole. Typical hardness is about 6–7 Mohs and specific gravity 2.63–2.75.
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Physical properties
Coarse-grained, speckled white/gray rock with dark mineral flecks and rusty weathering; vitreous quartz and blocky feldspar, no obvious cleavage as a whole. Typical hardness is about 6–7 Mohs and specific gravity 2.63–2.75.
Formation & geological history
Forms when silica-rich magma slowly crystallizes deep underground, producing interlocking crystals; individual pieces may be millions to billions of years old depending on source. Surface weathering can create the rough, brown-stained appearance.
Uses & applications
Widely used as dimension stone, countertops, monuments, aggregate, and decorative landscaping material; this small specimen has minimal commercial value.
Geological facts
The light grains are probably feldspar and quartz, while black grains may be biotite or hornblende. Exact identification would require a fresh surface, hand lens, and possibly thin-section or chemical testing.
Field identification & locations
Common worldwide, especially in continental mountain belts and exposed cratons. Look for visible interlocking crystals, glassy gray quartz, white/pink feldspar, and dark mica; it is distinguished from marble by its granular silicate minerals and lack of calcite fizz.
