igneous
Weathered granite or granitic gneiss pebble
Granite; primarily quartz, potassium feldspar, plagioclase, and mica
AI-generated identification · may be incorrectCoarse, speckled gray-white rock with dark mica/minerals and a granular texture; likely Mohs 6–7, vitreous to dull luster, interlocking crystals, and no obvious cleavage as a whole rock. The rounded shape indicates abrasion or tumbling.
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Physical properties
Coarse, speckled gray-white rock with dark mica/minerals and a granular texture; likely Mohs 6–7, vitreous to dull luster, interlocking crystals, and no obvious cleavage as a whole rock. The rounded shape indicates abrasion or tumbling.
Formation & geological history
Likely crystallized slowly from silica-rich magma deep underground, commonly during Precambrian to younger continental crust formation; surface weathering and transport rounded it into a pebble. If foliated internally, it may instead be granitic gneiss, a metamorphic equivalent.
Uses & applications
Commonly used as aggregate, road stone, building stone, countertops, landscaping gravel, and decorative tumbled rock; this small specimen has little commercial value.
Geological facts
Granite’s visible grains record slow cooling, allowing large crystals to form. Dark flecks are commonly biotite or hornblende, while the pale grains are feldspar and quartz.
Field identification & locations
Identify it by its salt-and-pepper appearance, hard granular surface, and lack of layering; a streak, glass-scratch, and close inspection with a loupe can confirm quartz and feldspar. Common worldwide, especially in continental mountain belts.
