igneous
Pink-and-gray granite cobble
Granite, chiefly quartz, potassium feldspar, and plagioclase with minor biotite/hornblende
AI-generated identification · may be incorrectCoarse-grained, massive, and rounded by transport or weathering; pink feldspar contrasts with gray quartz and dark mafic minerals. Hardness is about 6–7 Mohs, vitreous to dull luster, no cleavage as a rock, and specific gravity about 2.6–2.7.
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Physical properties
Coarse-grained, massive, and rounded by transport or weathering; pink feldspar contrasts with gray quartz and dark mafic minerals. Hardness is about 6–7 Mohs, vitreous to dull luster, no cleavage as a rock, and specific gravity about 2.6–2.7.
Formation & geological history
An intrusive felsic igneous rock crystallized slowly from magma deep in the crust, commonly during Precambrian to younger continental plutonism; the rounded form is a transported or weathered cobble.
Uses & applications
Used as dimension stone, paving, aggregate, landscaping stone, countertops, and monuments; this specimen has modest decorative or educational value.
Geological facts
The pink color usually comes from potassium feldspar, while dark speckles commonly represent biotite or amphibole. Granite’s visible interlocking crystals distinguish it from volcanic rhyolite.
Field identification & locations
Identify it by its granular interlocking texture, abundant pale/pink feldspar, gray quartz, and scattered dark minerals; common worldwide in mountain belts, glacial deposits, river gravels, and quarry waste.
