metamorphic

Weathered schist

Mica schist, likely quartz–biotite/muscovite schist

AI-generated identification · may be incorrect

Typically Mohs 2–3 for mica and about 7 for quartz; brown, gray, bronze, and rusty colors with a reflective micaceous luster. Strong schistosity produces flaky layers and irregular cleavage; quartz-rich patches are harder and massive.

Identified September 3, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when shale or other clay-rich sediment was subjected to moderate-to-high heat and pressure during regional metamorphism, commonly in mountain-building belts. Its exact geological age cannot be determined from the photograph.

Uses & applications

Used locally as dimension stone, wall stone, landscaping rock, and aggregate; attractive mica-rich pieces may be collected but are rarely jewelry-grade.

Geological facts

The glittering surfaces come from aligned mica flakes, while rusty zones usually reflect weathering of iron-bearing minerals such as biotite or pyrite.

Field identification & locations

Identify it by pronounced foliation, sparkly flakes, and layers that split along mica-rich planes; it is commonly found in metamorphic mountain terrains worldwide. A hand lens and streak, hardness, and acid tests help distinguish it from gneiss or slate.