igneous
Rounded pink granitic cobble
Granite, likely pink alkali-feldspar granite or granitic gneiss; primarily quartz, feldspar, and mica
AI-generated identification · may be incorrectHardness about 6–7 Mohs; pink, gray, and white mottling with a granular texture and dull-to-glassy quartz luster. Interlocking crystals are typical; cleavage occurs in feldspar, while quartz has none. Exact identification is limited because the specimen is weathered and rounded.
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Physical properties
Hardness about 6–7 Mohs; pink, gray, and white mottling with a granular texture and dull-to-glassy quartz luster. Interlocking crystals are typical; cleavage occurs in feldspar, while quartz has none. Exact identification is limited because the specimen is weathered and rounded.
Formation & geological history
Formed by slow cooling of silica-rich magma deep in the crust, probably during Precambrian or younger continental-crust formation; later uplift, erosion, and transport rounded it into a cobble.
Uses & applications
Used as durable aggregate, dimension stone, paving material, and landscaping rock; attractive pieces may be polished for decorative objects, but this specimen has little gem value.
Geological facts
The pink color commonly comes from potassium feldspar, while dark flecks are likely biotite or amphibole. Its rounded shape indicates transport by water, glacial ice, or long-term abrasion.
Field identification & locations
Identify it by visible interlocking pink/white/gray grains, abundant quartz, and lack of layering or vesicles; common in glacial deposits, stream gravels, and areas near granite bedrock. A hand lens and scratch test help distinguish it from softer sandstone or concrete.
