Abstract
Voidites in purely type IaB diamonds, in which the former are found in random distributions not associated with transformed {001} platelets, have been studied in detail. The evidence from extra, subsidiary spots seen in the electron diffraction patterns from volumes of crystal containing voidites, and from Moiré fringes in voidite images, indicates a crystalline phase with a tetragonal unit cell as the voidite content. In this respect, these voidites differ from those seen in association with transformed platelets, in which earlier workers detected face-centred cubic structures. Otherwise, the atomic species comprising the voidite material is apparently the same in the two cases, since electron energy-loss spectroscopy in the present case indicates, likewise, a phase that gives a strong nitrogen signal.
