One of the speakers was Mr. Dominic Mok (Principal, Asian Gemmological Institute) and his topic entitled “Advanced Identification of Gemstones and Diamond”. Firstly, Mr. Mok briefed the natural gemstone included natural diamond and natural coloured gemstone. Then he explained the purpose of Gem Testing which aimed to identify the Natural, Treated and Synthetic Gems.

Then Mr. Dominic Mok mentioned Instrumentation of Gem Testing which separated into Conventional Gemmological Instruments (e.g. Microscope) and Advanced Instruments (e.g. FTIR, EDXRF, Raman, UV-VIS, etc). There were four types of diamonds in the following diagram.

The advanced diamond testing instruments were introduced and they were DiamondSure, DiamondView and DiamondPlus. DiamondSure used to identify Natural Type Ia and provided opinions on Type IaB, Type II, as well as reference for not diamond. DiamondView used very short UV. It identified Type Ia Diamond (with blue fluorescence), Type Ib (with greenish yellow fluorescence) and Type IIa (with bluish green fluorescence) as well as octahedral growth pattern. DiamondPlus was a mini Raman Spectrometer with detection stage cooled by LN2. It used to confirm natural diamond Type IIa and reference to CVD Synthetic or HPHT (High Pressure High Temperture) treatment. After that he stated the UV-Vis Spectrometer with D-N-C Probe which was able to help mounted diamonds as little as 0.01 carats.

The identification of coloured gemtones and pearl (Natural, Cultured with Salt-water & Fresh-water) using advanced instruments (e.g. EDXRF, FTIR, and Cathodoluminescence (CL)) were also discussed. Finally, Dominic mentioned the testing of Jadeite / Fei Cui in which separated into Type A, Type B and Type C, as well as, Type B+C. 

Lastly, Mr. Dominic Mok concluded that advanced testing instruments were necessary for testing conclusions including CVD synthetic diamonds, Paraiba tourmaline, Resin-impregnated jadeite / Fei Cui and Synthetic jadeite, etc.