Host: The Gemmological Society of Japan
Pages 8
A HPHT treated color typeⅡ a pink diamond with remarkable NV centers showed 498nm and 505nm photoluminescence（PL） peaks, which rarely appear in HPHT treated diamonds. Natural color typeⅡ a pink and brown diamonds were compared with the HPHT treated pink diamond here. Among 71 natural color pink and 100 brown diamonds, 4 pink and 36 brown diamonds showed both 498nm and 505nm peaks. Only 2 brown diamonds of them exhibited distinct NV peaks in PL spectra, but these peaks are weaker than the ones of the HPHT treated diamonds. Although 3 pink diamonds showed remarkable NV centers, both 498nm and 505nm peaks did not appear in them. Above 2 brown and 3 pink diamonds exhibited GR1, which was not present in the HPHT treated pink diamond.
