igneous
Quartz-bearing granite or granitic pegmatite
Felsic intrusive rock, chiefly quartz (SiO₂), feldspar, and minor mica
AI-generated identification · may be incorrectCoarse, crystalline texture with pale gray-white quartz/feldspar and brownish weathered areas; vitreous to dull luster and no obvious foliation. Typical hardness is about 6–7 Mohs, with poor cleavage overall; exact identification is limited by the image.
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Physical properties
Coarse, crystalline texture with pale gray-white quartz/feldspar and brownish weathered areas; vitreous to dull luster and no obvious foliation. Typical hardness is about 6–7 Mohs, with poor cleavage overall; exact identification is limited by the image.
Formation & geological history
Formed by slow cooling of silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic intrusive events. Weathering may produce the brown surface discoloration.
Uses & applications
Used as crushed aggregate, building stone, countertops, monuments, and decorative material; attractive crystals may be collected but this specimen appears low-grade.
Geological facts
Granite is defined by abundant quartz and alkali/plagioclase feldspar; visible interlocking grains distinguish it from many sedimentary rocks. The pale portion may also represent a quartz-rich vein or pegmatitic zone.
Field identification & locations
Look for interlocking visible grains, quartz’s glassy gray appearance, feldspar’s blocky cleavage, and mica’s reflective flakes. Common worldwide, especially in large continental batholiths; acid testing is generally unnecessary.
