igneous
Weathered granite or granitic gneiss
Granite; primarily quartz, feldspar, and mica (exact identification is uncertain from the photograph)
AI-generated identification · may be incorrectCoarse-grained, gray and speckled with a dull to faintly glassy luster; visible interlocking mineral grains and no obvious cleavage. Hardness is approximately 6–7 Mohs; specific gravity about 2.6–2.7.
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Physical properties
Coarse-grained, gray and speckled with a dull to faintly glassy luster; visible interlocking mineral grains and no obvious cleavage. Hardness is approximately 6–7 Mohs; specific gravity about 2.6–2.7.
Formation & geological history
Likely crystallized slowly from silica-rich magma deep underground, generally during Precambrian to Phanerozoic continental crust formation; surface weathering produced the rough edges and muted color.
Uses & applications
Commonly used as crushed stone, aggregate, building stone, countertops, monuments, and paving; this small weathered fragment has little commercial value.
Geological facts
Granite’s interlocking crystals make it resistant to abrasion and weathering, though feldspar commonly alters to clay, producing a rough surface.
Field identification & locations
Look for visible quartz (glassy gray), feldspar (white or pink), and dark mica or amphibole; a fresh broken surface should show a granular texture. Common worldwide, especially in continental shields and mountain batholiths.
