metamorphic

Weathered mica schist

Mica schist, likely muscovite–biotite schist with quartz and feldspar

AI-generated identification · may be incorrect

Typically Mohs 2–3 for mica and about 6–7 for quartz; dark brown to gray, with a sparkly micaceous sheen and pronounced foliation. Visible flaky layers, quartz/feldspar grains, and irregular cleavage are characteristic; bulk specific gravity is approximately 2.7–2.9.

Identified September 3, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when shale or another clay-rich sediment was subjected to elevated temperature and pressure during regional metamorphism, commonly during mountain building. The image alone cannot establish its geological age; schists range from Precambrian to recent tectonic belts.

Uses & applications

Used locally as building stone, wall stone, landscaping material, and aggregate, though strong foliation limits some construction uses. Attractive pieces may be collected, but this specimen appears ordinary rather than gem quality.

Geological facts

Mica flakes reflect light as glittering patches, while deformation can produce wavy or folded foliation. Iron oxidation may create the brown-orange weathering visible on the surface.

Field identification & locations

Identify it by its planar fabric, easily visible mica flakes, and tendency to split along foliation; a hand lens should reveal quartz and feldspar. Common in Appalachian, New England, European Alpine, Himalayan, and other metamorphic mountain belts.