igneous
Weathered granitic rock (likely granite or granodiorite)
Granite–granodiorite; quartz + feldspar + biotite/hornblende
AI-generated identification · may be incorrectCoarse, mottled pink-white-gray texture with dark mineral flecks; likely Mohs 6–7, vitreous to dull luster, interlocking grains, and no obvious cleavage as a whole rock. The rounded, stained surface suggests weathering; the pale patches could include altered feldspar or quartz.
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Physical properties
Coarse, mottled pink-white-gray texture with dark mineral flecks; likely Mohs 6–7, vitreous to dull luster, interlocking grains, and no obvious cleavage as a whole rock. The rounded, stained surface suggests weathering; the pale patches could include altered feldspar or quartz.
Formation & geological history
A plutonic igneous rock crystallized slowly from magma deep underground, probably during Mesozoic or older continental-arc magmatism; later uplift and weathering exposed it. This is common around the Inland Northwest near Spokane, Washington.
Uses & applications
Used as crushed stone, aggregate, building stone, monuments, and landscaping; attractive pieces may be collected as cabinet specimens, though this fragment has limited gem value.
Geological facts
Pink coloration commonly comes from potassium feldspar, while dark specks are biotite or hornblende. Surface iron staining and alteration can make granitic rocks look more tan or rusty than fresh material.
Field identification & locations
Look for visibly interlocking quartz, feldspar, and dark grains; a glassy gray quartz grain and hardness sufficient to scratch glass support identification. A streak, acid test, and fresh broken surface would help distinguish granite from granodiorite or weathered gneiss.
