Spectroscopic Characteristics of Treated-Color Natural Diamonds

Figure 5

Photoluminescence spectra were taken at liquid-nitrogen temperatures for most of the samples using three laser excitation wavelengths of 473, 532, and 785 nm. Strong H3 center, NV center, GR1 center, and H2 center were observed in some of these treated-color diamonds. The presence and/or absence of these centers have an indicative role to determine the type of treatment and the process of the treatment.