Production of pits and hillocks on (111) faces of synthetic diamond by etching

Octahedral faces of synthetic diamonds having dendrites on them have been etched in NaNO₂ at 800 °C and triangular pits with sharp corners and edges and rectilinear sides have been produced. By successive etching of the same region for three different periods it has been shown how the neighbouring pits enlarge, interact with each other and thus produce a triangular hillock surrounded by three triangular pits of opposite orientation.