metamorphic
Mica schist
Mica-rich schist, commonly muscovite–biotite schist with quartz and feldspar
AI-generated identification · may be incorrectMedium- to coarse-grained, dark gray and strongly foliated, with abundant reflective mica flakes producing a silvery sheen. Mica has Mohs hardness 2–3 and perfect basal cleavage; quartz and feldspar are harder (about 6–7), with schistose, platy crystal alignment.
Identified More metamorphic →
Explore Mica schist in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Medium- to coarse-grained, dark gray and strongly foliated, with abundant reflective mica flakes producing a silvery sheen. Mica has Mohs hardness 2–3 and perfect basal cleavage; quartz and feldspar are harder (about 6–7), with schistose, platy crystal alignment.
Formation & geological history
Forms when shale or other clay-rich sediment is subjected to regional metamorphism, typically during mountain building; the exact geological age cannot be determined from the photograph. Commonly develops in metamorphic belts and ancient continental crust.
Uses & applications
Used locally as decorative facing stone, landscaping rock, and aggregate, though strong foliation limits structural use; attractive pieces may be collected but are rarely gem-grade.
Geological facts
The glitter comes from aligned mica cleavage surfaces rather than metallic ore. Weathering can cause mica schist to split into thin slabs and produce unstable slopes.
Field identification & locations
Identify it by pronounced layering or wavy foliation, abundant sparkly mica, and easy splitting along planar surfaces; common in the Appalachian, Rocky, Scandinavian, and Himalayan metamorphic belts. A hand lens and streak, cleavage, or hardness tests help distinguish it from shiny slate or graphite-bearing rock.
More like this
