metamorphic
Mica Schist
Mica Schist (Quartz-Biotite-Muscovite Schist)
Hardness: 3.5–4.0; Color: Silvery-gray, greenish-gray, or brown; Luster: Pearly to sub-metallic; Crystal Structure: Foliated/Platy; Cleavage: Perfect basal cleavage in mica flakes; Specific Gravity: 2.7–3.0
- Hardness
- 3
- Color
- Silvery-gray, greenish-gray, or brown
- 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: 3.5–4.0; Color: Silvery-gray, greenish-gray, or brown; Luster: Pearly to sub-metallic; Crystal Structure: Foliated/Platy; Cleavage: Perfect basal cleavage in mica flakes; Specific Gravity: 2.7–3.0
Formation & geological history
Formed by the regional metamorphism of shale or mudstone under intermediate to high temperatures and pressures. This transition occurs within the earth's crust during mountain-building events (orogenies).
Uses & applications
Primarily used as decorative stone, flagstone, or building material. Historically used for roofing slates. Micas within it are used in the electronics and cosmetics industry after extraction.
Geological facts
The word schist is derived from the Greek word 'schizein', meaning 'to split', referring to the ease with which the rock can be cleaved along its foliation planes. Large flakes of mica create a characteristic 'sheen' or 'sparkle' when held to light.
Field identification & locations
Identify by its strong shistosity (distinct layering) and the presence of visible mica flakes that reflect light like tiny mirrors. Commonly found in metamorphic terranes such as the Appalachian Mountains, Alps, or Himalayas. Collectors look for accessory minerals like Almandine Garnet trapped within the layers.
More like this
