| Graphite is one of the softest materials known. | Synthetic nanocrystalline diamond is the hardest material known.[23] |
| Graphite is a very good lubricant, displaying superlubricity.[24] | Diamond is the ultimate abrasive. |
| Graphite is a conductor of electricity.[25] | Diamond is an excellent electrical insulator,[26] and has the highest breakdown electric field of any known material. |
| Some forms of graphite are used for thermal insulation (i.e. firebreaks and heat shields), but some other forms are good thermal conductors. | Diamond is the best known naturally occurring thermal conductor |
| Graphite is opaque. | Diamond is highly transparent. |
| Graphite crystallizes in the hexagonal system.[27] | Diamond crystallizes in the cubic system. |
| Amorphous carbon is completely isotropic. | Carbon nanotubes are among the most anisotropicmaterials ever produced. |
