Schist (Chlorite or Mica-rich)

Physical Properties

Hardness: 2-3 (Mohs scale); Color: Greenish-gray to dark gray; Luster: Pearly to vitreous; Crystal Structure: Foliated (schistose); Cleavage: Perfect in one direction, creating flaky sheets; Specific Gravity: Approx. 2.7-2.9.

Formation & Geological History

Formed through regional metamorphism of clay-rich sedimentary rocks or mafic igneous rocks under intermediate pressure and temperature conditions. It is typically found in Precambrian or Paleozoic metamorphic belts.

Uses & Applications

Used primarily in construction for decorative stone, garden walls, or as crushed stone for road fill; occasionally used in carving or as a source of industrial minerals if high in specific flakes.

Geological Facts

The word 'Schist' is derived from the Greek word 'schizein', meaning 'to split', referring to how the rock easily breaks along its foliation planes. Large flakes of mica or chlorite give it its signature shimmer.

Field Identification & Locations

Identify in the field by its distinct platy or flaky appearance and its ability to be split into thin layers. It often has a glittery or greasy sheen due to the presence of mica or chlorite minerals. Common in mountain ranges and ancient shield regions.

Identified on: 4/20/2026

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