metamorphic
Mica Schist
Mica Schist (primarily Muscovite and Quartz composition)
Hardness: 3.5-4 on Mohs scale; Color: Silver-grey to brownish; Luster: Pearly to metallic (very reflective flakes); Structure: Foliated with visible mica alignment; Cleavage: Basal cleavage in mica minerals; Specific Gravity: 2.7-3.0
- Hardness
- 3
- Color
- Silver-grey to brownish
- Luster
- Pearly to metallic (very reflective flakes)
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3.5-4 on Mohs scale; Color: Silver-grey to brownish; Luster: Pearly to metallic (very reflective flakes); Structure: Foliated with visible mica alignment; Cleavage: Basal cleavage in mica minerals; Specific Gravity: 2.7-3.0
Formation & geological history
Formed through the regional metamorphism of shale or mudstone at medium grades of pressure and temperature. This transformation occurs during mountain-building events where clay minerals recrystallize into large, visible mica flakes.
Uses & applications
Used as building stone, flagstone, and decorative wall veneer. Fine-ground mica is used as a lubricant, in electrical insulation, and in the cosmetics industry to add shimmer to makeup.
Geological facts
The term 'Schist' comes from the Greek word 'schistos,' meaning 'easily split,' referring to its tendency to break along planes. Large flakes of mica called 'books' can sometimes be found within this rock type.
Field identification & locations
Identify in the field by its 'schistosity'—a sparkly, glitter-like appearance caused by the parallel alignment of mica minerals. It is commonly found in mountain belts like the Appalachians, Alps, and Himalayas. Collectors should look for 'garnet-mica schist' which often contains small reddish crystal inclusions.
More like this
