The mineral graphite, as with diamond and fullerene, is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): "to draw/write", for its use in pencils, where it is commonly called lead, as distinguished from the actual metallic element lead. Unlike diamond, graphite is an electrical conductor, a semimetal, and can be used, for instance, in the electrodes of an arc lamp. Graphite holds the distinction of being the most stable form of carbon under standard conditions. Therefore, it is used in thermochemistry as the standard state for defining the heat of formation of carbon compounds. Graphite may be considered the highest grade of coal, just above anthracite and alternatively called meta-anthracite, although it is not normally used as fuel because it is hard to ignite.

There are three principal types of natural graphite, each occurring in different types of ore deposit: (1) Crystalline flake graphite (or flake graphite for short) occurs as isolated, flat, plate-like particles with hexagonal edges if unbroken and when broken the edges can be irregular or angular; (2) Amorphous graphite occurs as fine particles and is the result of thermal metamorphism of coal, the last stage of coalification, and is sometimes called meta-anthracite. Very fine flake graphite is sometimes called amorphous in the trade; (3) Lump graphite (also called vein graphite) occurs in fissure veins or fractures and appears as massive platy intergrowths of fibrous or acicular crystalline aggregates, and is probably hydrothermal in origin.

The name "graphite fiber" is also sometimes used to refer to carbon fibre or carbon fibre reinforced plastic.

Occurrence

Graphite has various other characteristics. Thin flakes are flexible but inelastic, the mineral can leave black marks on hands and paper, it conducts electricity, and displays superlubricity. Its best field indicators are softness, luster, density and streak.

According to the USGS, world production of natural graphite in 2006 was 1.03 million tonnes and in 2005 was 1.04 million tonnes (revised), of which the following major exporters produced: China produced 720,000 tonnes in both 2006 and 2005, Brazil 75,600 tonnes in 2006 and 75,515 tonnes in 2005 (revised), Canada 28,000 tonnes in both years, and Mexico (amorphous) 12,500 tonnes in 2006 and 12,357 tonnes in 2005 (revised). In addition, there are two specialist producers: Sri Lanka produced 3,200 tonnes in 2006 and 3,000 tonnes in 2005 of lump or vein graphite, and Madagascar produced 15,000 tonnes in both years, a large portion of it "crucible grade" or very large flake graphite. Some other producers produce very small amounts of "crucible grade".