igneous
Likely pink granite or potassium-feldspar-rich rock
Granite; chiefly quartz (SiO₂), feldspar (KAlSi₃O₈–NaAlSi₃O₈), and minor mica/amphibole
AI-generated identification · may be incorrectSmall pale pink, opaque, dull-to-slightly granular specimen with an irregular fracture; individual grains are poorly resolved. Typical granite hardness is 6–7 Mohs, non-cleavable overall, and specific gravity about 2.6–2.7.
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Physical properties
Small pale pink, opaque, dull-to-slightly granular specimen with an irregular fracture; individual grains are poorly resolved. Typical granite hardness is 6–7 Mohs, non-cleavable overall, and specific gravity about 2.6–2.7.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in continental crust, commonly during Precambrian or younger intrusive events. The Duluth–northeastern Minnesota region near 46.7°N, 92.0°W contains abundant Precambrian igneous rocks, making this identification regionally plausible.
Uses & applications
Used as building stone, crushed aggregate, monuments, countertops, and landscaping material; small pieces have modest collecting value.
Geological facts
The pink color generally comes from potassium feldspar, while gray/clear grains would be quartz and dark flakes may be biotite or hornblende.
Field identification & locations
A fresh broken surface should show interlocking pink/white feldspar, glassy quartz, and possibly black mica. A hand lens, streak test (white), and hardness test help; certainty requires a clearer close-up or thin section because the specimen could also be pink feldspar, quartzite, or weathered pegmatite.
