Carbon is a non-metallic element with symbol C and atomic number 6. Important isotopes include C-12, C-13 and C-14. Carbon forms many allotropes, some of which are important as construction materials; these are collectively known as diamondoid, a class of materials which includes pure diamond (in particular nanoassembled perfect crystalline diamond), Adamant, graphene, carbon nanotubes, aggregated carbon nanorods, pandifico and diamondoid computronium. Allotropes that are less strong include graphite and amorphous carbon, such as soot (which may include a small buckyball content).
Carbon is an important element in most forms of organic chemistry, due to its unique chemical bonding characteristics; it is also found in many minerals and rocks, especially on carbon worlds.