Graphite is a polymorph of carbon typically formed through the metamorphism of organic material found in mineral deposits. It can also appear during the formation of igneous rocks or as nodules inside of iron meteorites.
Metamorphism is the alteration of existing solid rocks due to increasing changes in temperature and pressure, as well as the introduction of chemically active fluids. During metamorphism, the existing rocks become unstable and break down to form new minerals but do so while remaining in a solid state rather than melting. Graphite is produced from the carbon atoms resulting from the metamorphism of minerals such as marble, quartz, calcite, micas, schist, gneiss and tourmaline. Being almost entirely carbon based, graphite shares the same chemical composition as diamonds, but the arrangement of molecules results in a different physical structure.
In its pure form, which can occur either in flakes or lumps, Graphite is an extremely soft, blackish mineral that is greasy to the touch. This combination of solidity and greasiness makes graphite an excellent dry lubricant suitable for a variety of industrial uses where wet lubricants such as oil would be unsuitable. As an ingredient, graphite is also used in the manufacture of a number of items such as batteries, brake linings and pencils.