metamorphic
Schist
Crystalline Schist (often containing Muscovite, Biotte, or Quartz)
Hardness: 3.5–4.5 on Mohs scale; Color: Silvery-gray to charcoal (often with a greenish tint from chlorite); Luster: Pearly to sub-metallic; Crystal structure: Foliated (platy); Cleavage: Perfect in one direction along mica planes; Specific gravity: 2.7–2.8
- Hardness
- 3
- Luster
- Pearly to sub-metallic
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3.5–4.5 on Mohs scale; Color: Silvery-gray to charcoal (often with a greenish tint from chlorite); Luster: Pearly to sub-metallic; Crystal structure: Foliated (platy); Cleavage: Perfect in one direction along mica planes; Specific gravity: 2.7–2.8
Formation & geological history
Formed through the regional metamorphism of shale or mudstone under intermediate-grade temperature and pressure conditions. This process aligns mineral grains into thin, wavy layers known as schistosity.
Uses & applications
Commonly used as a decorative building stone, in paving, for retaining walls, and occasionally as a source of industrial minerals like garnet or mica. It is also used as landscape stone.
Geological facts
The term 'schist' is derived from the Greek word 'schistos,' meaning 'split,' referring to the ease with which the rock can be cleaved into thin plates. It represents a higher grade of metamorphism than phyllite but lower than gneiss.
Field identification & locations
Identify in the field by its distinct 'shimmer' or 'glitter' when held in the sun, caused by aligned mica flakes. Look for wavy, foliation planes. Commonly found in Appalachian Mountains and various metamorphic belts globally.
More like this
