metamorphic

Likely schist with quartz-rich fragments

Mica schist, likely biotite schist; exact identification is uncertain from the image

AI-generated identification · may be incorrect

Dark gray, strongly foliated, sparkly surface with platy mica; typically Mohs 2–3 for mica and 6–7 for quartz, with a glassy to pearly luster and poorly defined cleavage at the rock scale.

Identified September 9, 2026More metamorphic →

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Physical properties

Dark gray, strongly foliated, sparkly surface with platy mica; typically Mohs 2–3 for mica and 6–7 for quartz, with a glassy to pearly luster and poorly defined cleavage at the rock scale.

Formation & geological history

Formed when shale or another clay-rich sediment was subjected to regional metamorphism, commonly during mountain building; age depends on locality and may range from Paleozoic to Precambrian.

Uses & applications

Used locally as decorative stone, roofing or wall stone, landscaping material, and a collector specimen; rarely used for high-wear construction because foliation causes splitting.

Geological facts

The layered texture reflects aligned mica grains produced by directed pressure and heat. The small brown specimen may be weathered schist or a separate mica- and quartz-rich metamorphic fragment.

Field identification & locations

Identify it by peeling or glittering foliation, visible mica flakes, and easy splitting along layers; distinguish slate by its larger mica crystals and stronger sparkle. Common in metamorphic mountain belts worldwide.