metamorphic
Graphite-bearing schist (probable)
Graphite schist; primarily quartz, mica, and graphite (carbon)
AI-generated identification · may be incorrectDark gray to black, platy and strongly foliated, with a greasy to submetallic luster; likely Mohs hardness 1–3 for graphite-rich surfaces, higher where quartz dominates. Graphite commonly leaves a black mark and conducts electricity; mica may show glittering cleavage flakes.
Identified More metamorphic →
Explore Graphite-bearing schist (probable) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray to black, platy and strongly foliated, with a greasy to submetallic luster; likely Mohs hardness 1–3 for graphite-rich surfaces, higher where quartz dominates. Graphite commonly leaves a black mark and conducts electricity; mica may show glittering cleavage flakes.
Formation & geological history
Formed when carbonaceous sedimentary rocks were buried and metamorphosed under heat and pressure, commonly during mountain building; exact age cannot be determined from the image. The foliation reflects mineral alignment during deformation.
Uses & applications
Used locally as a source of graphite, though most specimens are collected for teaching or display; schist has limited construction value because it splits readily. Graphite-rich material may be used in lubricants, refractories, batteries, and electrodes.
Geological facts
The shiny black flakes could also include biotite or another dark mica, so laboratory testing is needed for certainty. A streak test, electrical-conductivity test, and thin-section or X-ray analysis would distinguish graphite from mica.
Field identification & locations
Common in metamorphic belts worldwide, including the Appalachians, Canadian Shield, Scandinavia, and Himalayan regions. Look for foliation, flexible or flaky cleavage, a dark streak, and possible quartz veins; avoid relying on color alone.
More like this
