metamorphic
Schist
Chlorite or Mica Schist
Hardness: 3.5-4 (Mohs); Color: Grey, green, or silvery; Luster: Pearl or silky (foliated sheen); Crystal structure: Platy/flaky minerals in parallel layers; Cleavage: Perfect mica-like foliation.
- Hardness
- 3
- Color
- Grey, green, or silvery
- Luster
- Pearl or silky (foliated sheen)
Identified More metamorphic →
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Physical properties
Hardness: 3.5-4 (Mohs); Color: Grey, green, or silvery; Luster: Pearl or silky (foliated sheen); Crystal structure: Platy/flaky minerals in parallel layers; Cleavage: Perfect mica-like foliation.
Formation & geological history
Formed through the regional metamorphism of shale or mudstone under intermediate to high temperatures and pressures. Often Precambrian or Paleozoic in age, occurring in mountain belts.
Uses & applications
Used in landscaping, decorative stone paving, and occasionally as a source of industrial minerals like mica or talc depending on the specific lithology.
Geological facts
The name 'schist' comes from the Greek word 'schizein', meaning 'to split', referring to how easily the rock breaks along its mineral layers.
Field identification & locations
Identify in the field by its 'schistosity'—a sparkly, layered appearance that breaks into thin sheets. Found in tectonic collision zones like the Appalachians or Alps.
