The common element in graphite, fullerene, diamond and graphene is:

Graphite, diamond, graphene, and fullerenes are all different physical forms of the same chemical element, carbon [1][2]. These forms are known as allotropes, which occur when atoms of the same element are bonded together in different structural arrangements [2]. Diamond consists of a giant tetrahedral network where each carbon atom is bonded to four others, making it the hardest natural substance [2]. Graphite is composed of layered sheets of carbon atoms arranged in hexagonal rings, which allows it to conduct electricity [1]. Graphene is a single, two-dimensional layer of these graphite sheets. Fullerenes, such as C-60 (buckminsterfullerene), consist of carbon atoms arranged in spherical or cage-like structures resembling a football [1]. Despite their vastly different physical properties, such as hardness and conductivity, their chemical identity remains purely carbon [1][3].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Allotropes of carbon > p. 61
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Table 3.1 > p. 40
3. [3] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > 4.1 BONDING IN CARBON – THE COVALENT BOND > p. 59