metamorphic
Mica Schist
Muscovite-Biotite Schist
Hardness: 2-2.5 (on mica flakes) to 6-7 (if containing quartz/garnet); Color: Silvery-gray, tan, or metallic gold-tone; Luster: Pearly to sub-metallic (schistose foliation); Crystal structure: Monoclinic (mica); Cleavage: Perfect basal cleavage in individual flakes.
- Hardness
- 2-2
- Color
- Silvery-gray, tan, or metallic gold-tone
- Luster
- Pearly to sub-metallic (schistose foliation)
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 2-2.5 (on mica flakes) to 6-7 (if containing quartz/garnet); Color: Silvery-gray, tan, or metallic gold-tone; Luster: Pearly to sub-metallic (schistose foliation); Crystal structure: Monoclinic (mica); Cleavage: Perfect basal cleavage in individual flakes.
Formation & geological history
Formed via regional metamorphism of shale or mudstone at middle-grade temperatures and pressures. Most common in mountain-building belts and Precambrian shields.
Uses & applications
Used as a historical building stone, decorative landscaping, and occasionally ground up for use in paints, drilling muds, or cosmic glitter in cosmetics.
Geological facts
The shimmering effect is caused by the alignment of mica crystals during intense tectonic pressure. If the specimen contains large visible flakes, it is definitively a schist rather than a phyllite or slate.
Field identification & locations
Identify by its sparkling 'glitter-like' appearance and tendency to flake off into thin plates. Commonly found in eroded metamorphic terrains like the Appalachian or Himalayan mountains.
More like this
