Differentiation of natural and synthetic gem-quality diamonds by luminescence properties

Abstract Laser-excited time-resolved and UV-excited static photoluminescence (PL) as well as cathodoluminescence (CL) techniques were applied to identify the origin of diamonds. Samples represented natural faced and rough diamonds from diamond market and different kimberlites as well as the most common high pressure–high temperature (HPHT) and as-grown synthetic diamonds. The time-resolved PL spectra of natural and synthetic diamonds display clear mutual differences. The static PL and CL spectra of natural diamonds revealed emission bands caused by complex nitrogen–vacancy (N–V)-aggregates whereas the bands of synthetic diamonds reflect simple N–V-aggregates and nickel-containing defects. The luminescence properties depended on the excitation method and also changed during the excitation. The study of PL colors revealed information about the emission distribution of the PL spectra giving possibilities for future applications. The results indicated the sensitivity of luminescence techniques and revealed interesting structural information about diamond materials.