Diamond used in jewellery is

Diamond is chemically classified as an element because it is composed entirely of a single type of atom: carbon [c1][t4]. In chemistry, an element is a pure substance that cannot be broken down into simpler substances by chemical means [c4]. Diamond is a crystalline allotrope of carbon, where each carbon atom is covalently bonded to four others in a rigid, three-dimensional tetrahedral structure [c1][t9]. Unlike compounds, which consist of two or more different elements chemically combined in fixed ratios, diamond contains only carbon atoms [c4][t3]. While natural diamonds used in jewellery may contain trace impurities like nitrogen, they are fundamentally considered the elemental form of carbon rather than a compound or a metal [t2][t8]. Carbon itself is a non-metal, and its allotropic forms like diamond and graphite represent the element in different structural arrangements [c2][t1].

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 VIII . NCERT(Revised ed 2025) > Chapter 8: Nature of Matter: Elements, Compounds, and Mixtures > Snapshots > p. 130
4. [4] https://www.bristol.ac.uk/Depts/Chemistry/MOTM/diamond/diamond.htm