metamorphic
Likely gneiss
Quartz–feldspar–mica gneiss
AI-generated identification · may be incorrectSmall, gray, coarse-grained stone with light and dark mineral flecks and possible weak banding. Typical minerals have Mohs hardness around 6–7; luster is mostly dull to glassy, with no obvious cleavage at this scale.
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Physical properties
Small, gray, coarse-grained stone with light and dark mineral flecks and possible weak banding. Typical minerals have Mohs hardness around 6–7; luster is mostly dull to glassy, with no obvious cleavage at this scale.
Formation & geological history
Gneiss forms when pre-existing rock is recrystallized under high heat and pressure, commonly deep in continental crust; its age depends on the source and region.
Uses & applications
Gneiss is used as building and paving stone, aggregate, and decorative facing; this small piece is mainly a field or collection specimen.
Geological facts
The visible speckled texture is consistent with interlocking quartz and feldspar plus darker mica or amphibole, but a photograph cannot confirm the identification.
Field identification & locations
Look for coarse interlocking grains and mineral segregation or banding; gneiss occurs in ancient continental shields and mountain belts worldwide. A close-up and fresh fracture would help distinguish it from granite or other metamorphic rocks.
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