Gemmological Characteristic of Green Synthetic Moissanite

Synthetic moissanite, as the third-generation semiconductor material with excellent thermal conductivity and semiconductor properties, has been widely recognized and applied in industrial fields such as new energy, new materials, and aerospace, etc. Additionally, the light yellow, and light green synthetic moissanites with high hardness, high refractive index, and high dispersion value widely used in domestic and foreign jewelry markets was once considered to be the best substitute for diamonds. However, there are less investigations on green synthetic moissanite. In this paper, the gemmological characteristics, colour genesis, and spectral characteristics of green synthetic moissanite samples were systematically studied using gem microscopes, infrared spectroscopy, UV-Visible spectroscopy, and laser Raman spectroscopy, in order to enrich the gemmological data of synthetic moissanite. The results show that the green synthetic moissanite samples are adamantine luster, refractive index above 1.78, and the specific gravity about 3.22. The infrared absorption spectroscopy analysis mainly shows Si-C stretching vibrations with relatively pure composition and partial lattice imperfections. The UV-visible absorption spectroscopy shows that the superficial donor energy level of N element is the main factor for moissanite's color. Moreover, the laser Raman spectroscopy reveals that the green synthetic moissanite samples are mainly 6H type accompanied by minor 15R type. Moissanite samples being 6H-15R polytype mixed structures are attributed to the concentrations of impurity elements and the uneven compositions which reduced the structural stability.