Schist

Physical Properties

Hardness: 3.5-4; Color: Silver-grey to glittery greenish-grey; Luster: Sub-metallic to pearly; Crystal Structure: Foliated with large visible grains; Cleavage: Perfect mica-type cleavage into thin sheets; Specific Gravity: 2.7-2.8

Formation & Geological History

Formed through the regional metamorphism of shale or mudstone under higher pressure and temperature than phyllite or slate. This creates characteristic 'schistosity' or layering.

Uses & Applications

Used primarily in decorative construction, flagstones, garden walls, and sometimes as a low-grade abrasive. Not widely used in heavy industry due to its tendency to split.

Geological Facts

Schist is the intermediate step in rock metamorphism between phyllite and gneiss. The name comes from the Greek word 'schizein', meaning 'to split'.

Field Identification & Locations

Identify in the field by its distinct glittery surface caused by large mica flakes and its tendency to split into irregular thin slabs. Often found in mountain ranges like the Appalachians or Alps.

Identified on: 5/1/2026

Mode: Standard