- a very common mineral, soft native carbon, occurring in black to dark-gray foliated masses, with metallic luster and greasy feel: used for pencil leads, as a lubricant, and for making crucibles and other refractories; plumbago; black lead.
- a blackish soft allotropic form of carbon in hexagonal crystalline form: used in pencils, crucibles, and electrodes, as a lubricant, as a moderator in nuclear reactors, and, in a carbon fibre form, as a tough lightweight material for sporting equipment
