igneous
Likely weathered granite or granitic pegmatite fragment
Granite; chiefly quartz (SiO₂), feldspar, and mica/amphibole
AI-generated identification · may be incorrectCoarse, irregular, mottled gray-brown specimen with visible interlocking grains and dull-to-glassy luster; typical hardness is about Mohs 6–7, with no obvious cleavage at this scale. Exact identification is limited by the small, blurry image and surface weathering.
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Physical properties
Coarse, irregular, mottled gray-brown specimen with visible interlocking grains and dull-to-glassy luster; typical hardness is about Mohs 6–7, with no obvious cleavage at this scale. Exact identification is limited by the small, blurry image and surface weathering.
Formation & geological history
Forms when silica-rich magma slowly cools deep underground, producing large crystals; most granite is Precambrian to Phanerozoic in age. Weathering or erosion may have liberated this fragment from an outcrop or construction aggregate.
Uses & applications
Granite is widely used for building stone, paving, countertops, monuments, and crushed aggregate; this small piece has negligible commercial value unless it proves to contain collectible crystals or ore minerals.
Geological facts
Quartz is commonly gray or translucent, feldspar is white to pink, and dark grains are biotite or hornblende. A glassy fracture, visible quartz, and interlocking grains help distinguish granite from sedimentary rocks.
Field identification & locations
Common worldwide, especially in continental mountain belts and shields; inspect with a hand lens and test for quartz, feldspar, and mica. Estimated value: $0–$5 as an ordinary fragment; $5–$20 if unusually attractive or mineralized.
