metamorphic

Mica-bearing metamorphic rock, likely schist

Muscovite–biotite schist, possibly phyllite

AI-generated identification · may be incorrect

Fine-grained, platy specimen with reflective golden-brown mica flakes and gray silicate matrix; mica has perfect basal cleavage and Mohs hardness about 2–3, while quartz/feldspar are about 6–7. The sheen and layered appearance indicate a foliated texture.

Identified September 16, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when shale or mudstone underwent regional metamorphism, causing clay minerals to recrystallize into aligned mica; likely Paleozoic or younger, though age cannot be determined visually. Common in mountain-building belts.

Uses & applications

Used mainly as landscaping stone, decorative aggregate, and an educational or collector specimen; mica may have minor industrial value, but this small piece is not typically valuable.

Geological facts

The glittering surfaces are mica cleavage planes rather than metallic crystals. Golden-brown flakes suggest biotite or weathered muscovite, and the dark spots may be iron-oxide staining or accessory minerals.

Field identification & locations

Identify it by strong foliation, easy splitting along shiny planes, and mixed light/dark mineral layers; it should not fizz with dilute acid. Common in metamorphic regions worldwide, including the Appalachians, Alps, and Himalayas.