metamorphic
Likely biotite-rich schist
Mica schist, composed chiefly of biotite and quartz; exact identification is uncertain from the image.
AI-generated identification · may be incorrectDark gray, fine- to medium-grained, with a flaky, sparkly surface and possible foliation. Biotite has Mohs hardness 2.5–3 and perfect basal cleavage; quartz, if present, is harder (Mohs 7).
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Physical properties
Dark gray, fine- to medium-grained, with a flaky, sparkly surface and possible foliation. Biotite has Mohs hardness 2.5–3 and perfect basal cleavage; quartz, if present, is harder (Mohs 7).
Formation & geological history
Formed when mica-bearing sedimentary or igneous rock was recrystallized under heat and pressure. Its age cannot be determined from the photograph.
Uses & applications
Schist is used locally as decorative or facing stone and is collected as a geological specimen; mica has industrial uses, though this small fragment has little practical value.
Geological facts
The visible flakes and layered appearance are consistent with mica-rich metamorphic rock, but the image is not sufficient to confirm the mineral composition.
Field identification & locations
Look for aligned, reflective mica flakes and a tendency to split along foliation; commonly found in regional metamorphic belts. A fresh surface and mineral tests would help distinguish schist from other dark rocks.
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