HPHT treatment of CO2 containing and CO2-related brown diamonds

摘要: Abstract Ten type I diamonds containing CO2 and three related to these (referred as “Pseudo CO2” diamonds) were treated by the HPHT process observe changes in colour, colour distribution, inclusions, luminescence spectral features visible mid-infrared regions. All samples of predominantly brown before treatment had rather inhomogeneous distribution not strain like classic Ia diamonds. Upon most them changed a more yellow hue, with greenish modifying but dominant was still brown. The modification found be much discreet than it is case for deformation-related diamond at all known centers such H3. modifications caused destruction broad absorption bands Vis–NIR spectrum generally increased transmission from 400 700 nm, likely slight increase single nitrogen, no typical annealing H3 H2 produced spectra samples. This could confirmed when excited shortwave longwave UV light, under which showed emission that practically modified treatment. infrared 10 diamonds, defined presence least stretching (ν3) bending (ν2) absorptions, unusually treatment: intensity low medium content, apparently diminished nitrogen-related one phonon absorptions (when present). In samples, lack definition peaks, peaks created reduced photoluminescence exhibiting several unpublished remained unchanged processing: none emissions annealed out new created. data obtained leads us propose, theory solid inclusions being responsible may erroneous, present structurally. Thus proposed structurally bonded oxygen play an important role study indicates can cases identified methods available well-equipped gemmological laboratories, since detectable defect appear induced