Figure 2. Transformation of hexagonal graphite with 0.214 nm interlayer distance into polycrystalline cubic diamond.

In the figure, the green and red balls represent atoms that have three and four nearest neighbors, respectively. (a). The initial state of hexagonal graphite with 0.214 nm interlayer distance. (b). The wave-like buckling of the graphite layers leads to the stacking order of the graphite layers transforming from “ABAB” to “ABCA” (rhombohedral graphite). (c). Parts of graphite convert into cubic diamond. (d). Graphite completely transforms into polycrystalline cubic diamond.