igneous
Weathered granitic rock
Granite, likely biotite granodiorite
AI-generated identification · may be incorrectCoarse-grained, mottled gray-white and brown surface with visible quartz, feldspar, and dark mica; quartz hardness 7, feldspar about 6, overall Mohs roughly 6–7, vitreous to dull luster, interlocking crystals, no obvious cleavage as a whole.
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Physical properties
Coarse-grained, mottled gray-white and brown surface with visible quartz, feldspar, and dark mica; quartz hardness 7, feldspar about 6, overall Mohs roughly 6–7, vitreous to dull luster, interlocking crystals, no obvious cleavage as a whole.
Formation & geological history
An intrusive igneous rock crystallized slowly from silica-rich magma deep underground, commonly during Precambrian to Phanerozoic continental pluton formation; the rounded shape and brown coating result from weathering and abrasion.
Uses & applications
Used as building stone, countertops, monuments, aggregate, and landscaping material; this small weathered piece has little jewelry value unless polished.
Geological facts
Granite’s light minerals are quartz and feldspar, while biotite or hornblende creates dark flecks. The specimen may also be granodiorite, which is difficult to distinguish confidently from a photograph.
Field identification & locations
Identify it by its speckled interlocking texture, hardness, and lack of layering or vesicles; common worldwide in continental crust and glacial deposits. A fresh broken surface would improve identification.
