HRD Antwerp has recently come across (near-) colourless lab grown diamonds featuring octahedral and other “natural” shapes. It noted that unlike previous times when it was easier to tell natural rough stones from lab grown diamonds owing to the typical cubo-octahedral shape seen with diamonds produced by HPHT (High Pressure High Temperature) and the characteristic plate structure of diamonds produced by CVD (Chemical Vapour Deposition) which significantly differs from the morphology of natural diamonds, this new occurrence of rough lab grown diamonds featuring a morphology previously unique to natural diamonds and entering the markets is making it more difficult for less experienced rough traders.

The rough melee goods examined by HRD Antwerp varied in size from 0.01 ct to 0.04 ct and were produced by Taidiam, a Chinese company offering both HPHT and CVD lab grown diamonds. “A more in-depth investigation on a microscopic level however still reveals the remnants of a seed crystal used to position the precipitated carbon atoms, and / or other characteristics inherent to lab grown diamonds. An infrared spectroscopy analyses by our research team has also demonstrated that all colourless diamonds included in the examination were found to be type IIa or type IIb” explains Dr Katrien De Corte, Chief Education Officer HRD Antwerp.

“The fact that lab grown diamonds now also occur in an octahedral shape merely affects the rough trade as once the diamonds are polished, dedicated equipment still provides a full proof solution for identifying lab grown diamonds in our lab” Mrs De Corte added.