metamorphic
Biotite-rich schist (probable)
Mica schist, likely biotite–quartz–feldspar schist; exact minerals require testing
AI-generated identification · may be incorrectCoarse, mottled brown-black and pale grains with reflective mica flakes and weak foliation. Biotite has Mohs hardness 2.5–3; quartz, if present, is 7; overall color and density vary with composition.
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Physical properties
Coarse, mottled brown-black and pale grains with reflective mica flakes and weak foliation. Biotite has Mohs hardness 2.5–3; quartz, if present, is 7; overall color and density vary with composition.
Formation & geological history
Formed when mica-bearing sedimentary or igneous rock was recrystallized under heat and pressure. Its age cannot be determined from the image and depends on the source region.
Uses & applications
Commonly used as decorative or landscaping stone and collected as a field specimen; mica-bearing schist has limited construction use because it can split along foliation.
Geological facts
The glistening surfaces are consistent with platy mica, while the irregular pale patches may be quartz or feldspar; a photo cannot confirm the identification.
Field identification & locations
Look for aligned, reflective flakes and a tendency to split into sheets; distinguish it from unfoliated granite by its planar mica fabric. Mica schists occur in metamorphic belts worldwide.
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