Amorphous graphite is a naturally occurring seam mineral that forms from the geologic metamorphism of anthracite coal. Contrary to the name, “amorphous” graphite is not truly amorphous, but is a microcrystalline form of natural graphite. The morphology of amorphous graphite is typically granular except in extremely fine grinds, which have a flaky structure. The term “amorphous” is applied to this form of natural graphite because the extremely small “crystallite” particles that make this material do not form crystal faces that are visible to the naked eye (anhedral opposed to euhedral.) “As mined” material is available in sizes ranging from mixed 1 cm and smaller particles to 10 cm lumps.
Amorphous graphite is the least graphitic of the natural graphites. However, the term "amorphous" is a misnomer since the material is still crystalline. Amorphous graphite is found as minute particles in beds of mesomorphic rocks such as coal, slate or shale deposits. The graphite content ranges from 25% to 85% dependent on the geological conditions.
Amorphous graphite is extracted using conventional mining techniques and occurs primarily in Mexico, North Korea, South Korea and Austria.