metamorphic

Mica schist

Mica schist, chiefly muscovite/biotite mica with quartz and feldspar

AI-generated identification · may be incorrect

Typically medium- to coarse-grained, strongly foliated, and sparkly with platy mica; this specimen is gray-brown with rusty orange iron-oxide staining. Hardness is about 2–3 for exposed mica and 6–7 for quartz, with excellent schistosity and mica cleavage; luster ranges from pearly to vitreous.

Identified September 18, 2026More metamorphic →

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Physical properties

Formation & geological history

Produced by medium-grade regional metamorphism of shale or other clay-rich sediment, commonly during mountain building; its exact geological age cannot be determined from the image. Heat and pressure aligned the mica into visible planar layers.

Uses & applications

Used locally as decorative stone, landscaping material, fill, and occasionally building veneer; attractive mica-rich pieces are collected, but this rough specimen has limited commercial value.

Geological facts

The glitter comes from reflected light on countless aligned mica flakes, and rusty zones generally indicate weathering of iron-bearing minerals.

Field identification & locations

Identify it by abundant visible mica, strong foliation, easy splitting along layers, and a streaky texture; common in metamorphic mountain belts worldwide, including the Appalachians, Alps, and Himalaya.