Graphite: The Soft Diamond

Graphite is made from the same element that makes up diamonds. Carbon is necessary for life as we know it and makes up the primary source of energy in coal and fossil fuels. Graphite is most often found in veins in metamorphic rocks. It comes about largely from changes occurring in organic material included in limestone deposits.

Graphite is very soft for a mineral. It is black and when crushed will leave a black mark behind, making it an excellent substance with which to make pencils. Graphite is generally found in one of two forms: flake or lump. Lump graphite is compact, while flake breaks into very small flakes that slide over one another without creating too much friction. This can make the mineral feel greasy and is the property that makes it a good dry lubricant. Graphite is unusual as a non-metallic mineral in that it can serve as a good conductor of electricity.

Abraham Gottlob Werner gave graphite its name in 1789. He took it from the Greek verb graphein which means "to write". Then, as now, it was used to make pencils. Currently, China leads the world in graphite production. It provides nearly half of the graphite used in the United States. Flake graphite is also mined in Brazil, Canada, and Madagascar. Lump graphite is commonly found in Sri Lanka. Graphite is not only found in nature, it can be produced artificially. However, natural deposits are still abundant and cheap, making manufacture currently impractical.

Beyond pencil "lead" and lubrication, graphite is used in extremely high heat applications because it does not easily melt or disintegrate. It can be found in the crucibles used in steel manufacture.

Interesting Side Note: Graphite in pencils is called "lead" because the original European name for the substance was "plumbago", which was derived from the Latin word for "lead"1.

1. Mineral Information Institute

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