metamorphic
Dark metamorphic rock, likely schist or phyllite
Quartz–mica schist/phyllite; chiefly quartz, mica, and feldspar
AI-generated identification · may be incorrectGray-brown, fine- to medium-grained, with abundant pale intersecting veins or foliation. Likely Mohs hardness 2–7 depending on grain; dull to weakly silky luster, irregular fracture, and no obvious cleavage at this viewing scale. The rounded form suggests stream wear.
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Physical properties
Gray-brown, fine- to medium-grained, with abundant pale intersecting veins or foliation. Likely Mohs hardness 2–7 depending on grain; dull to weakly silky luster, irregular fracture, and no obvious cleavage at this viewing scale. The rounded form suggests stream wear.
Formation & geological history
Formed when clay-rich sedimentary rock was buried and regionally metamorphosed, developing mica-rich foliation; commonly Paleozoic to Mesozoic in age depending on source terrain. The reported Khuzestan location is dominated by sedimentary rocks, so a transported metamorphic pebble is more plausible than local bedrock.
Uses & applications
Mostly a field or teaching specimen; schist may be used locally as decorative stone or aggregate, but this small piece has negligible commercial value and is not gem quality.
Geological facts
The pale lines may be quartz veins, and the dark reflective patches may be biotite or graphite. A polished surface or thin section would be needed to distinguish schist from phyllite confidently.
Field identification & locations
Look for planar mica alignment, sparkly cleavage surfaces, and quartz-rich veins; a steel nail may scratch mica-rich areas but not quartz. Common sources include metamorphic mountain belts and river gravels. Estimated value: $1–$10 as an ordinary specimen.
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