Phosphorescence in type IIb diamonds

Spectroscopic properties, including phosphorescence spectroscopy, were collected for 354 natural type IIb diamonds, 7 natural type IIa diamonds, along with 24 HPHT-treated diamonds and 18 HPHT synthetic diamonds. The only phosphorescence bands observed in the natural diamonds were centered at 500 and 660 nm. The relative intensity and half-life of these measured bands corresponded well with the boron concentration. None of the treated or synthetic diamonds showed the 660 nm band. However, these samples did have the 500 nm band; the synthetics had much higher intensity than the comparable natural diamonds. The phosphorescence spectra are correlated to data collected from infrared absorption and photoluminescence spectroscopy and these results provide additional evidence of the mechanism responsible for the observed phosphorescence.

Research highlights► Collected phosphorescence spectroscopy on over 350 natural type IIb diamonds. ► Natural type IIb diamonds have phosphorescence bands at 500 and 660 nm. ► HPHT-synthetic and HPHT-treated diamonds do not show the 660 nm band.