Optical Properties of Natural and Synthetic Beryl Crystals

Optical absorption and luminescence studies of fast neutron-irradiated complex oxides for jewellery applications

“…4. As earlier reported [39][40][41][42][43], an irradiation produces 0 3 NO and 3 CO − type radicals, which seem to be related to blue colors in a beryl. We suppose that the band with the maximum at 690 nm belongs to a complex center consisting of Cr 3+ ions and radiation defects.…”

First-Principles Study of Optical Absorption Energies, Ligand Field and Spin-Hamiltonian Parameters of Cr3+ Ions in Emeralds

“…To rationalize the different properties between natural and synthetic gemstones, spectroscopy is a very helpful tool for structural refinement, detection of impurities, and identification of structural water, among many other uses. In fact, numerous experimental techniques such as Fourier transform infrared spectroscopy, Raman spectroscopy, UV–vis–NIR spectroscopy, PL, spectral hole-burning, and electron paramagnetic resonance (EPR) spectroscopy have been employed to study both natural − and synthetic emeralds. ,− Furthermore, various spectroscopic studies comparing natural and synthetic emeralds found remarkable differences between them. − …”

Characterization of Low Grade Natural Emerald Gemstone

“…When it is excited at 326 nm wavelength, the emission bands are shifted towards longer wavelengths, 536 and 556 nm, (Figure 12b) indicating the red shift. These emission bands are attributed to Cr 3+ ion substituted at Al site, electronic transitions involved for Cr 3+ ion corresponding to 4A 2g (F) → 4T 2g (F) according to the literature [20].…”