metamorphic

Likely graphite-rich schist or graphite-bearing metamorphic rock

Graphite (C) in a mica/quartz-rich matrix; exact rock name requires testing

AI-generated identification · may be incorrect

Dark gray-black, finely flaky and reflective with a soft, greasy feel; graphite has Mohs hardness 1–2, opaque metallic-to-submetallic luster, and no cleavage in massive form. The note that it is not heavy and leaves a black mark strongly supports graphite, though the image may also show mica or weathered carbonaceous m…

Identified September 1, 2026More metamorphic →

Explore Likely graphite-rich schist or graphite-bearing metamorphic rock in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed when carbon-rich sedimentary rocks were metamorphosed, commonly during regional mountain-building; graphite deposits range from Precambrian to younger ages. If the surface is unusually friable, it could instead be carbonaceous shale or an industrial carbon product.

Uses & applications

Graphite is used in pencils, lubricants, refractories, batteries, electrodes, and specialized composites; attractive schist specimens are mainly collector material.

Geological facts

Graphite is a crystalline form of carbon and is an excellent electrical and thermal conductor despite being very soft. It can mark unglazed porcelain or paper black.

Field identification & locations

Common in metamorphic terrains worldwide, including Sri Lanka, Madagascar, Canada, China, and the United States. Confirm by a black streak, very low hardness, greasy feel, and electrical conductivity; a steel knife should scratch it easily.