metamorphic

Foliated metamorphic rock, likely quartz-mica schist

Quartz–mica schist, commonly containing muscovite/biotite and quartz

AI-generated identification · may be incorrect

Gray to silvery, strongly foliated with wavy, flaky layers and a micaceous sheen; quartz-rich grains are hard (Mohs 7), while mica is about Mohs 2–3. Typically has no consistent cleavage as a whole, though mica separates readily along foliation; specific gravity is about 2.6–2.8.

Identified September 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when shale or another clay-rich sedimentary protolith was buried and subjected to elevated temperature and directed pressure, producing schistosity. It may range from Precambrian to younger ages depending on its regional metamorphic setting.

Uses & applications

Used locally as decorative stone, wall facing, landscaping rock, and aggregate, though strong foliation limits structural use; attractive pieces may be collected but are rarely valuable.

Geological facts

The silvery sparkle comes from aligned mica flakes, and the rock may split into thin irregular sheets. Its foliation records the direction of tectonic compression during metamorphism.

Field identification & locations

Identify it by its layered, crinkled texture, visible mica sparkle, and quartz-rich gray composition; common in mountain belts and exposed metamorphic terranes. A hand lens and streak/cleavage tests help distinguish it from gneiss or foliated granite.