igneous
Coarse-grained igneous rock, likely granite or granodiorite
Granite–granodiorite; chiefly quartz, feldspar, and biotite/hornblende
AI-generated identification · may be incorrectGray to pink, speckled, granular texture with visible interlocking crystals; likely Mohs 6–7, vitreous quartz luster, feldspar cleavage, and no obvious layering. Exact identification is limited by the small, weathered fragment and image lighting.
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Physical properties
Gray to pink, speckled, granular texture with visible interlocking crystals; likely Mohs 6–7, vitreous quartz luster, feldspar cleavage, and no obvious layering. Exact identification is limited by the small, weathered fragment and image lighting.
Formation & geological history
Forms when silica-rich magma slowly cools deep underground, producing coarse crystals; specimens may range from Precambrian to Cenozoic in age. Common in continental crust, mountain roots, and exposed plutons.
Uses & applications
Used widely as building stone, countertops, monuments, aggregate, and paving; attractive pieces are collected but generally inexpensive.
Geological facts
Quartz appears glassy gray, feldspar is white or pink, and dark mica or amphibole creates the black flecks. Granodiorite contains more plagioclase and darker minerals than typical granite.
Field identification & locations
Identify by its visible interlocking crystals, hardness, and lack of foliation; a streak test is usually white, and dilute acid causes no reaction. Common worldwide, especially in mountain belts and continental shields.
