igneous
Reddish granite or granitic gneiss pebble
Felsic granitoid, primarily quartz, potassium feldspar, plagioclase, and dark biotite/amphibole
AI-generated identification · may be incorrectCoarse crystalline texture with pink-red feldspar, gray quartz, and dark minerals; typically Mohs 6–7, vitreous to dull luster, no obvious cleavage, and specific gravity about 2.6–2.7. The visible streaking may indicate weak gneissic banding or weathering.
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Physical properties
Coarse crystalline texture with pink-red feldspar, gray quartz, and dark minerals; typically Mohs 6–7, vitreous to dull luster, no obvious cleavage, and specific gravity about 2.6–2.7. The visible streaking may indicate weak gneissic banding or weathering.
Formation & geological history
Formed from slowly cooled silica-rich magma, likely Precambrian to Paleozoic in age; rounded edges suggest transport as a river or glacial pebble. If banding is genuine, it may represent metamorphosed granite.
Uses & applications
Used as crushed stone, aggregate, dimension stone, landscaping material, and decorative cobbles; attractive pieces may be polished for display.
Geological facts
Pink coloration commonly comes from potassium feldspar, while dark bands reflect biotite or amphibole. Granite and gneiss are among the most widespread continental rocks.
Field identification & locations
Identify by visible interlocking crystals, hardness, and pink feldspar; it should not fizz with dilute acid and will usually scratch glass. Common in continental shields, mountain belts, glacial deposits, and river gravels.
