igneous
Quartz-rich rock fragment, possibly mica-bearing pegmatite
Likely quartz–feldspar–mica aggregate; exact identification requires testing
AI-generated identification · may be incorrectSmall, irregular, pale gray-white specimen with sparkly reflective flakes and dark inclusions. Likely hardness about 6–7 Mohs, vitreous to pearly luster, uneven fracture, and no obvious cleavage visible at this scale.
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Physical properties
Small, irregular, pale gray-white specimen with sparkly reflective flakes and dark inclusions. Likely hardness about 6–7 Mohs, vitreous to pearly luster, uneven fracture, and no obvious cleavage visible at this scale.
Formation & geological history
Most consistent with a weathered fragment of granite or pegmatite formed when silica-rich magma crystallized slowly underground, generally during Precambrian to Phanerozoic geological periods. The dark material may be biotite mica or another accessory mineral.
Uses & applications
Common granite and pegmatite are used as aggregate, dimension stone, and sources of quartz and feldspar; attractive pieces may be collected but this fragment has little commercial value.
Geological facts
The visible sparkle may come from mica cleavage surfaces rather than metallic minerals. A glassy translucent grain would support quartz, while blocky cleavage and opaque white grains suggest feldspar.
Field identification & locations
Identify in the field by testing: quartz scratches glass and lacks cleavage; feldspar is softer and shows two cleavage directions; mica peels into thin sheets. Common in granitic terrains and stream gravels worldwide.
