metamorphic
Mica Schist
Mica Schist (primarily Muscovite or Biotite sheets with Quartz)
Hardness: 2-3 (mica) to 7 (quartz components); Color: silvery-gray to brownish-tan; Luster: Pearly to sub-metallic; Crystal structure: Monoclinic (sheety); Cleavage: Perfect basal cleavage; Specific gravity: 2.7–3.0
- Hardness
- 2-3 (mica) to 7 (quartz components)
- Color
- silvery-gray to brownish-tan
- Luster
- Pearly to sub-metallic
Identified More metamorphic →
Explore Mica Schist in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 2-3 (mica) to 7 (quartz components); Color: silvery-gray to brownish-tan; Luster: Pearly to sub-metallic; Crystal structure: Monoclinic (sheety); Cleavage: Perfect basal cleavage; Specific gravity: 2.7–3.0
Formation & geological history
Formed through the regional metamorphism of shale or mudstone at intermediate temperatures and pressures. This process causes clay minerals to recrystallize into large, visible flakes of mica oriented perpendicularly to the direction of pressure.
Uses & applications
Primarily used as a decorative stone in landscaping, flagstone for walkways, and occasionally as a source of scrap mica for industrial insulation or as a filler in construction materials.
Geological facts
The word schist is derived from the Greek word 'schizein' meaning 'to split', referring to the ease with which these rocks can be flaked into thin plates. It characterizes a specific metamorphic grade between phyllite and gneiss.
Field identification & locations
Identify in the field by its 'schistosity'—a distinct layering of shiny, platy minerals that reflect light like tiny mirrors. It is common in mountainous regions and metamorphic terranes such as the Appalachians or the Alps.
More like this
