corundum, color.4, treatments.6, gems

This paper, which constitutes a small portion of an on‐going project, is an update on the presence in the market of beryllium treated blue sapphires, the types of material and their identifying characteristics. Five commercial quality (in the 1ct range) beryllium treated blue sapphires that are representative of a large parcel recently purchased on the Bangkok market are described with details of their chemistry, inclusion scenes and optical data. Further, two large 22ct and 53ct beryllium treated blue sapphires that are reportedly treated by a different technique are also described. The data reveals several types of start material are used for the beryllium treatment of blue sapphires but that in each case there are important clues that lead the gemologist toward the nature of the treatment with the ultimate test being analysis using LA‐ICP‐MS.