igneous
Weathered granite
Granite; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, mottled gray, pink, and brown surface with granular texture and dull to slightly vitreous luster; quartz is Mohs 7, while overall hardness varies by mineral. No obvious foliation or bedding is visible; iron-oxide staining and weathering obscure the original crystals.
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Physical properties
Coarse-grained, mottled gray, pink, and brown surface with granular texture and dull to slightly vitreous luster; quartz is Mohs 7, while overall hardness varies by mineral. No obvious foliation or bedding is visible; iron-oxide staining and weathering obscure the original crystals.
Formation & geological history
Intrusive felsic magma cooled slowly deep within the crust, producing interlocking crystals; commonly Paleozoic to Precambrian in exposed continental crust. The reddish-brown areas likely reflect oxidation of iron-bearing minerals during surface weathering.
Uses & applications
Widely used as building stone, monuments, countertops, paving, aggregate, and crushed stone. This weathered field specimen has little gem or collector value.
Geological facts
Granite is defined by abundant quartz and feldspar and is one of Earth’s most common continental crust rocks. Its pink coloration typically comes from potassium feldspar, whereas dark patches commonly contain biotite or amphibole.
Field identification & locations
Common in continental mountain belts, shields, and granitic plutons worldwide. Identify it by visible interlocking quartz and feldspar grains, lack of layering, and a speckled appearance; a fresh broken surface is more diagnostic than this weathered exterior.
