igneous
Granite (weathered, possibly granitic gneiss)
Granite; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, pink-gray, speckled texture with visible feldspar and dark mafic minerals; typically Mohs 6–7, vitreous quartz luster, massive structure, and poor cleavage as a whole rock. The slab appears weathered and fractured, so exact identification is limited from the photograph.
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Physical properties
Coarse-grained, pink-gray, speckled texture with visible feldspar and dark mafic minerals; typically Mohs 6–7, vitreous quartz luster, massive structure, and poor cleavage as a whole rock. The slab appears weathered and fractured, so exact identification is limited from the photograph.
Formation & geological history
Slow cooling of silica-rich magma deep in the crust formed interlocking crystals, commonly during Precambrian to Phanerozoic continental mountain-building; uplift and erosion exposed it. The planar breaks may reflect natural joints or quarrying.
Uses & applications
Widely used for building stone, curbs, monuments, countertops, paving, and crushed aggregate; ordinary field specimens have little jewelry value.
Geological facts
Pink coloration usually comes from potassium feldspar, while gray translucent grains are quartz. Granite commonly develops rounded weathering surfaces and iron-oxide staining outdoors.
Field identification & locations
Look for interlocking visible crystals, abundant quartz, pink/white feldspar, and scattered black biotite or hornblende; it is not layered like sandstone or slate. Common worldwide, especially in continental shields and mountain belts.
