igneous
Quartz-rich granite or granitic pegmatite fragment
Granite; predominantly quartz (SiO₂), feldspar, and minor mica/iron oxides
AI-generated identification · may be incorrectCoarse, granular, pale gray-white specimen with translucent quartz and likely feldspar; vitreous quartz luster, uneven fracture, Mohs hardness about 6–7, no obvious cleavage on quartz. Exact mineral proportions are uncertain from the image.
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Physical properties
Coarse, granular, pale gray-white specimen with translucent quartz and likely feldspar; vitreous quartz luster, uneven fracture, Mohs hardness about 6–7, no obvious cleavage on quartz. Exact mineral proportions are uncertain from the image.
Formation & geological history
Formed by slow crystallization of silica-rich magma deep in the crust, commonly during Precambrian to Phanerozoic continental plutonism; surface fragments may derive from weathered bedrock or gravel.
Uses & applications
Granite is widely used as dimension stone, countertops, monuments, aggregate, and building material; attractive quartz-rich pieces have modest collecting interest.
Geological facts
Granite commonly shows interlocking crystals rather than layered or glassy texture. A hand lens can help distinguish glassy quartz from cleavable, blocky feldspar.
Field identification & locations
Common worldwide, especially in continental shields and mountain belts. Identify with a granular texture, quartz that scratches glass, and feldspar cleavage; vinegar or dilute acid should produce no reaction unless carbonate is present.
