Abstract
Diamonds have been etched by heating on a molybdenum filament in a low pressure (about 2.5μ Hg) of oxygen. The etch figures obtained by this method have the same orientation as those obtained by etching in oxidizing melts, but differ in outline by being sharply triangular. They are in fact similar in all respects, except for the inverted orientation, to the natural features called ‘trigons’. It is therefore concluded, contrary to recently accepted opinion, that the latter are also probably etch figures, produced by an unknown natural etching process. Note : Unless the edge of the crystal is in the field of view, all upright triangles are etch pits.

This publication has 2 references indexed in Scilit: