AGS Laboratories said it will resume grading Type IIa and Type IaB diamonds as it has purchased additional equipment capable of detecting sophisticated treatment techniques. The laboratory had temporarily halted grading for these two types of diamonds in late 2005 because the diamonds can be high pressure, high temperature (HPHT) treated in order to improve their colour � something that the lab couldn�t detect at the time with its existing equipment.
AGS later conducted a review of the advanced treatment techniques and the available detection methodologies, which included discussions with some of the industry�s leading experts, before purchasing the new equipment and performing in-depth testing to ensure that HPHT treated stones can be accurately identified.
As part of the new process for grading the treated diamonds, the laboratory will add comments to each of its documents when testing for treatment is a factor. In very rare cases when the lab cannot conclusively determine through testing that a diamond has been HPHT treated, it will include the following comments: �Industry standard testing was inconclusive as to whether this diamond has been high pressure, high temperature (HPHT) processed to improve its appearance.�
�We�re confident through our research and technology that we are offering our clients the most thorough testing available,� said AGS Laboratories executive director Peter Yantzer.