metamorphic
Likely biotite-rich mica schist
Mica schist, chiefly biotite (K(Mg,Fe)₃AlSi₃O₁₀(OH,F)₂), with possible quartz and feldspar
AI-generated identification · may be incorrectDark brown-black, glittery, and visibly foliated or flaky; biotite has Mohs hardness 2.5–3 and perfect basal cleavage. The small specimen’s exact minerals cannot be confirmed from the image alone.
Identified More metamorphic →
Explore Likely biotite-rich mica schist in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark brown-black, glittery, and visibly foliated or flaky; biotite has Mohs hardness 2.5–3 and perfect basal cleavage. The small specimen’s exact minerals cannot be confirmed from the image alone.
Formation & geological history
Forms when clay-rich or other sedimentary rocks undergo regional metamorphism, aligning mica flakes into shiny layers. Its age depends on the local metamorphic event and cannot be determined visually.
Uses & applications
Schist is used as decorative or landscaping stone and occasionally as building stone; mica is used in electrical, industrial, and cosmetic products.
Geological facts
Schistosity is the characteristic planar texture created by aligned platy minerals, which often sparkle in reflected light.
Field identification & locations
Look for a foliated texture and flakes that split into thin sheets; common in metamorphic belts worldwide. A close-up or mineral tests would help distinguish mica schist from other dark, glittery rocks.
More like this
