Crystallization of natural polycrystalline diamonds from cuboid to ballas

Abstract

We examined the microtexture and crystallographic orientation feature of natural diamonds (cuboid & ballas) using EBSD. Cuboid shows a variety of texture from single-crystalline to polycrystalline with increase in crystallographic misorientation between adjacent fibrous crystals growing radially to the rim. Ballas consists of radiating fibrous to columnar crystals accompanied by larger misorientation angles between them. These features suggest that successional change in growth mechanism is expected for the formation of single-crystalline to polycrystalline diamonds.