A ‘Diamond Typing Service’ has been launched by the International Gemological Institute (IGI) at its New York laboratory. The purpose of the service is to identify the diamonds which are suitable to undergo high pressure high temperature (HPHT) colour treatment process and artificial irradiation.

The rational behind this approach is that if a diamond is suitable for colour treatment, the knowledge on its type helps establish the method and conditions for treatment (temperature, pressure, irradiation, etc.) and also in forecasting the colour of the diamond after treatment.

The diamond type is determined basis its concentration levels of nitrogen or boron, classifying it into Ia, Ib, IIa and IIb.

The IGI will accept up to 10 diamonds, regardless of individual weight, at its New York lab. The service will cost $150 and will have a turnaround time of 48 hours.