igneous
Weathered granitic rock (likely granite or granodiorite)
Granite–granodiorite; primarily quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse, speckled gray-white texture with dark mica or amphibole; typically Mohs 6–7, vitreous quartz luster, interlocking crystals, and poor cleavage as a whole rock. The rounded edges indicate stream or surface weathering.
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Physical properties
Coarse, speckled gray-white texture with dark mica or amphibole; typically Mohs 6–7, vitreous quartz luster, interlocking crystals, and poor cleavage as a whole rock. The rounded edges indicate stream or surface weathering.
Formation & geological history
Formed when silica-rich magma slowly crystallized deep underground, generally during Precambrian to younger continental crust formation; later exposed and weathered. Exact age cannot be determined from the photograph.
Uses & applications
Commonly used as crushed stone, aggregate, building stone, countertops, monuments, and landscaping material; this small weathered piece has little commercial value.
Geological facts
Granite is an intrusive igneous rock, while granodiorite contains slightly more plagioclase and darker minerals. Surface staining and weathering can obscure its original mineral proportions.
Field identification & locations
Identify it by visible interlocking white/gray feldspar, translucent quartz, and scattered black mica or amphibole; a hand lens and hardness test help distinguish it from quartz-rich sandstone or concrete. Common worldwide in continental mountain belts and glacial or stream gravels.
