igneous
Granite
Coarse-grained felsic intrusive igneous rock; mainly quartz, potassium feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectLikely gray granite with interlocking visible crystals and granular texture; quartz has vitreous luster, feldspar is whitish, and dark mica/amphibole forms black grains. Hardness is approximately 6–7 Mohs; cleavage occurs in feldspar, while the rock itself has no cleavage.
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Physical properties
Likely gray granite with interlocking visible crystals and granular texture; quartz has vitreous luster, feldspar is whitish, and dark mica/amphibole forms black grains. Hardness is approximately 6–7 Mohs; cleavage occurs in feldspar, while the rock itself has no cleavage.
Formation & geological history
Formed by slow cooling and crystallization of silica-rich magma deep in Earth’s crust, typically during Precambrian to Phanerozoic intrusive events; exact age cannot be determined from the image.
Uses & applications
Widely used as building stone, countertops, monuments, paving, aggregate, and landscaping rock; attractive polished varieties are used decoratively, but this fragment has little gem value.
Geological facts
The speckled “salt-and-pepper” appearance reflects contrasting felsic minerals and dark mafic minerals. Grain size and composition can overlap with granodiorite, so laboratory identification may be needed.
Field identification & locations
Identify it by its hard, dense, unlayered, interlocking grains and inability to scratch easily with a steel knife; common worldwide in continental mountain belts and exposed batholiths.
