metamorphic
Mica-rich metamorphic rock, likely schist
Muscovite–biotite schist, possibly quartz-bearing
AI-generated identification · may be incorrectVisible platy, reflective mica flakes in a foliated, coarse-grained matrix; likely hardness 2–3 for mica and ~7 for quartz, with pearly to vitreous luster, uneven cleavage, and specific gravity around 2.7–3.0.
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Physical properties
Visible platy, reflective mica flakes in a foliated, coarse-grained matrix; likely hardness 2–3 for mica and ~7 for quartz, with pearly to vitreous luster, uneven cleavage, and specific gravity around 2.7–3.0.
Formation & geological history
Formed when clay-rich sedimentary rock underwent regional metamorphism, aligning mica minerals into foliation under heat and pressure, commonly during mountain building. Exact geological age cannot be determined from the photograph.
Uses & applications
Used locally as decorative stone, landscaping material, aggregate, or occasionally roofing/foliation stone; ordinary specimens have little jewelry value.
Geological facts
The glitter is produced by light reflecting from mica cleavage surfaces, not necessarily metallic ore. Rust-colored areas may represent iron oxidation or weathered biotite.
Field identification & locations
Identify it by its layered texture and flakes that split into thin sheets; quartz-rich areas are harder and do not peel. Common in metamorphic belts worldwide, including the Appalachians, Scandinavia, India, and Africa.
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