Crystal forms of synthetic diamonds

The cubic crystal is composed of (100) faces, and the octahedron is composed of (111) faces, different orientation has different hardness. The (111) face is the hardest one, and the (100) face is softer. Our HPHT monocrystal diamond are (100) orientations, while the CVD monocrystal diamond, both (100), (110) and (111) orientations are available upon customers’ requirements.

To some extent, it is more difficult to grind the (111) face than to grind the (100) face for diamond tool makers.

In general, high-pressure and high-temperature (HPHT) synthesis, hexoctahedral round materials tend to be synthesized, because this crystal form has better wear resistance, strength, toughness, impact toughness, magnetic susceptibility and other properties, and the synthesis range is large, which could be controlled easily and widely be used.

Especially, the octahedral diamond, this crystal form is the one tried to be avoided during the synthesis, because the synthesis of this kind of octahedral diamond usually requires a high synthesis temperature, the surface integrity of the prepared octahedral diamond is not high, and the unit yield is low and the cost is high. It runs relatively high risks for synthesis equipment, which is difficult to meet the practical application of industrial production.