Editing Graphite (section)

=== Natural ===
Graphite occurs naturally in [[ore]]s that can be classified as either ''amorphous'' (microcrystalline) or ''crystalline'' (flake or lump/chip) which is determined by the ore [[Polymorphism (materials science)|morphology]], [[crystallinity]], and [[grain size]].<ref name="USGS_PP1802J"/> All naturally occurring graphite deposits are formed from the [[metamorphism]] of [[carbonaceous]] [[sedimentary rocks]], and the ore type is due to its geologic setting. [[Coal]] that has been thermally metamorphosed is the typical source of amorphous graphite. Crystalline flake graphite is mined from [[carbonaceous]] [[metamorphic rocks]], while lump or chip graphite is mined from veins which occur in high-grade [[metamorphic]] regions.<ref name="USGS_PP1802J"/> There are serious negative environmental impacts to graphite mining.