Two Pieces of Sapphires Treated by Be and Ti Multiple Diffusion

The laboratory of the Gold and Diamond Testing Center of China(NGDTC)encountered two pieces of Be and Ti diffused sapphires.When the facet junctions near the culets of two stones are observed in immersion,colour appears darker,which means two stones have been diffused by Ti element.Chemical analysis by the laser ablation inductively coupled plasma mass(LA-ICP-MS)shows the Be concentrations are 23,14ppma respectively in the surface layers of two stones,which indicates they have been also diffused by Be element.As we all know,Be diffusion of corundum must always be carried out in a highly oxidizing atmosphere,but Ti diffusion process should undergo in a reducing atmosphere.Considering the possible course,the authors believe that the stones have been heated through multiple procedures,which makes it hard to identify the diffusion because common evidence of Be diffusion has been deleted.As advisable disclose,it is enough to state that the stone is dif-fused.The trade does not need to focus too much on the roles of Be and/or Ti in these stones when they are in market.