Graphite is the crystal of carbon, is a non-metallic material, silver gray color, soft, with a metallic luster. Mohs hardness is 1-2, specific gravity is 2.2-2.3, and its bulk density is generally 1.5-1.8.

Graphite has a very high melting point, which tends to melt when it is softened to 3000 C in vacuum. Graphite begins to evaporate and sublimate at 3600 C. The strength of general materials decreases gradually at high temperature. When graphite is heated to 2000 C, its strength is doubled compared with that at normal temperature, but the oxidation resistance of graphite increases gradually with the increase of temperature.

The thermal conductivity and electrical conductivity of graphite are quite high. Its electrical conductivity is 4 times higher than that of stainless steel, 2 times higher than that of carbon steel and 100 times higher than that of non-metal. Its thermal conductivity not only exceeds that of steel, iron, lead and other metal materials, but also decreases with the increase of temperature, which is different from general metal materials. Graphite even tends to be adiabatic at extremely high temperature. Therefore, the thermal insulation performance of graphite is very reliable under the condition of ultra-high temperature.

Graphite has good lubricity and plasticity. Graphite friction coefficient is less than 0.1. Graphite can be developed into breathable and transparent thin sheets. The hardness of high strength graphite is so high that it is difficult to process with diamond tools.

Graphite has chemical stability, acid and alkali resistance, and corrosion resistance to organic solvents. Graphite has been widely used in modern industry because of its unique properties.