Micro-Raman Spectroscopy Study of Gem-Quality Diamond-Like Nexus Labs Stone and its Comparison to Natural and Synthetic Polished Diamonds

Abstract

Dispersive (visible) confocal micro-Raman spectroscopy (DCμRS) was non-destructively performed on a gem-cut diamond-like nexus labs stone, which is the most popular gem on the market today to characterization and identification. The observed Raman bands were compared and contrasted to the natural mined diamond and synthetic produced chemical vapour deposotion diamond in order to distinguish them from one another. A total 9 of Raman bands were observed in the spectra of the representative diamond-like nexus labs stone which was firstly synthesized from the elements C, S, Ca, Fe, Co, Ni, Y, Zr, Gd, and Hf. Then covered by corundum and related material composite. They showed bands at 170, 312, 520, 727, 918, 1079, 1112, 1332 and 1523 cm^-1 in a range between 50 and 1600 cm^-1 and they are characteristic for this stone, which is fully colourless. In addition, possible causes of these bands were assigned to some crystalline defects. It can be stated that only one Raman band at 1332 cm^-1 can be related to the characteristic crystalline diamond band, since the strong characteristic carbon Raman band representing a covalent bonding at 1332 cm^-1 in the natural and synthetic diamonds. Additionally, one weaker characteristic Raman band also appear at 1349 cm^-1 in the synthetic chemical vapour deposition pure-carbon lab-created diamond, which is yellowish only. Moreover, the weak band is due to the ionic bonded [AlO₄] centre which composed of corundum covering.