metamorphic
Mica Schist
Mica Schist (composed mainly of Muscovite / Biotite, Quartz, and Feldspar)
Hardness: 3.5-4 (varies depending on quartz content); Color: Silvery-gray, greenish-gray, to brownish; Luster: Pearly to sub-metallic, highly sparkly; Structure: Foliated schistose texture with parallel alignment of mica flakes; Cleavage: Perfect basal cleavage in individual mica grains; Specific Gravity: 2.7-3.0.
- Hardness
- 3
- Color
- Silvery-gray, greenish-gray, to brownish
- Luster
- Pearly to sub-metallic, highly sparkly
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: 3.5-4 (varies depending on quartz content); Color: Silvery-gray, greenish-gray, to brownish; Luster: Pearly to sub-metallic, highly sparkly; Structure: Foliated schistose texture with parallel alignment of mica flakes; Cleavage: Perfect basal cleavage in individual mica grains; Specific Gravity: 2.7-3.0.
Formation & geological history
Formed through regional metamorphism of clay-rich sedimentary rocks (like shale or mudstone) under intermediate temperatures and pressures, causing platy mica minerals to align perpendicularly to maximum stress direction.
Uses & applications
Used historically as decorative dimension stone and flagstone; industrial mica is extracted for electrical insulation, cosmetics, and paints; frequently collected as introductory geology specimens.
Geological facts
Mica schist is known for its intense sparkle when catching light due to thousands of aligned microscopic to visible mica flakes. Garnet crystals frequently form as porphyroblasts within mica schist.
Field identification & locations
Easily identified by its glittery surface, flaky texture, and distinct foliated layers. Highly abundant in metamorphic terranes worldwide, including mountain chains like the Appalachians and Alps.
More like this
