Weathered mica schist

Usually Mohs 2–3 for mica and ~7 for quartz; brown-gray, sparkly, foliated, with visible platy mica, uneven fracture, and moderate density. The specimen shows strong schistosity and surface weathering/iron staining.

Formed when shale or other clay-rich sediment was subjected to regional metamorphism, producing aligned mica and recrystallized quartz; commonly Paleozoic to Precambrian in exposed mountain belts, though age depends on locality.

Used locally as decorative stone, wall stone, landscaping material, and occasionally roofing or aggregate; attractive mica-rich pieces are collected but are rarely gem-grade.

Its glitter comes from reflective mica cleavage surfaces rather than metallic mineral crystals. Brown coloration commonly results from oxidation of iron-bearing biotite or sulfide minerals.

Identify it by foliation, glittering flexible mica flakes, and alternating light quartz-rich and dark mica-rich layers; it should split along foliation rather than show uniform granular texture. Common in metamorphic mountain terrains worldwide, including the Appalachians, Alps, and Himalaya.