igneous
Pink granite or granitic gneiss pebble
Granitic rock, mainly quartz, feldspar, and mica; possibly weathered gneiss
AI-generated identification · may be incorrectHardness about 6–7 Mohs; pale pink, white, and gray with darker wisps; dull to weakly crystalline luster. The rounded shape indicates stream or beach abrasion, while the image suggests coarse interlocking grains and faint mineral banding; cleavage is absent as a whole rock.…
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Physical properties
Hardness about 6–7 Mohs; pale pink, white, and gray with darker wisps; dull to weakly crystalline luster. The rounded shape indicates stream or beach abrasion, while the image suggests coarse interlocking grains and faint mineral banding; cleavage is absent as a whole rock. Exact identification is limited because individual grains are not sharply resolved.
Formation & geological history
Formed when silica-rich magma cooled slowly deep underground, likely billions of years old in the ancient Precambrian crust. Near 43.5°N, 86.0°W, glacial transport commonly brings Canadian Shield granitic and metamorphic rocks into beach and glacial deposits.
Uses & applications
Used as crushed stone, aggregate, dimension stone, monuments, and decorative landscaping material. This small rounded piece has little commercial value but is suitable as a display or teaching specimen.
Geological facts
The pink color usually comes from potassium feldspar; gray translucent grains are quartz, and dark flecks may be biotite or amphibole. A streaked texture would favor gneiss over ordinary granite.
Field identification & locations
Look for visible pink feldspar, glassy gray quartz, and black mica in an interlocking texture; a glassy surface, bubbles, or uniform color would suggest a non-rock material. Common around Great Lakes glacial deposits and shorelines.
