The "Diamond Structure" refers to the arrangement of carbon atoms in a diamond crystal. In this structure, each carbon atom is bonded to four other carbon atoms in a three-dimensional tetrahedral configuration. This strong bonding creates a rigid and highly stable lattice, which is responsible for diamond's exceptional hardness. Diamonds are a form of carbon, and their unique structure contributes to their optical properties, such as brilliance and fire. The arrangement allows for the efficient dispersion of light, making diamonds highly sought after in jewelry. The diamond structure is a key factor in distinguishing diamonds from other forms of carbon, like graphite.