metamorphic

Micaceous schist

Mica schist, commonly quartz–muscovite/biotite schist

AI-generated identification · may be incorrect

Typically gray, silver, brown, or reddish with a glittery vitreous-to-pearly luster and strong foliation from aligned mica flakes; quartz and feldspar produce granular areas. Hardness is about 2–3 for mica and 6–7 for quartz, with perfect mica cleavage and variable specific gravity around 2.7–2.9.

Identified August 19, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when shale or other clay-rich sedimentary rock underwent medium-grade regional metamorphism, generally during mountain building; its exact age cannot be determined from the image. Commonly associated with folded, deformed metamorphic belts.

Uses & applications

Used locally as decorative stone, landscaping material, wall cladding, and aggregate, but its foliation limits structural construction use. Attractive pieces are collected, though it is rarely a high-value gemstone material.

Geological facts

The visible sparkle comes from reflective mica sheets, while reddish tones may reflect iron oxides or garnet-bearing material. Splitting along foliation is a key feature.

Field identification & locations

Look for thin, aligned mica flakes, glitter, wavy layering, and easy splitting; distinguish it from granite by its pronounced foliation. Common in the Appalachians, New England, Scottish Highlands, Alps, and other ancient mountain belts.