metamorphic
Weathered mica-rich metamorphic rock
Likely schist or phyllite; composition probably quartz, mica, and feldspar
AI-generated identification · may be incorrectGray-green, strongly foliated, flaky texture with dull to slightly silky luster; individual mica layers may be soft (Mohs 2–3), while quartz-rich areas approach Mohs 7. Cleavage is prominent along foliation; exact identification is limited by the blurred image.
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Physical properties
Gray-green, strongly foliated, flaky texture with dull to slightly silky luster; individual mica layers may be soft (Mohs 2–3), while quartz-rich areas approach Mohs 7. Cleavage is prominent along foliation; exact identification is limited by the blurred image.
Formation & geological history
Formed when shale or mudstone underwent regional metamorphism, realigning clay minerals into mica; commonly Paleozoic or older, depending on locality. It likely originated in a metamorphic terrane and was later weathered or transported.
Uses & applications
Used locally as decorative stone, landscaping aggregate, or occasionally dimension stone; attractive mica-rich pieces may be collected but are generally low-value.
Geological facts
Schistosity results from aligned mica flakes and allows the rock to split into thin sheets. Green coloration may reflect chlorite, indicating relatively low- to medium-grade metamorphism.
Field identification & locations
Look for visible, parallel mica flakes and easy splitting; a glassy quartz-rich fracture helps distinguish schist from phyllite. Common in mountain belts worldwide, including the Appalachians, New England, Colorado, and Scotland.
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