Identification Characteristic of "Recrystallized Snythetic Emerald"

Abstract

Recently, a kind of "recrystallized emerald" that claims to be created from natural emerald powder appeared in the market. In order to figure out its identification characteristics, on the basis of conventional gemmological testing, several other testing instruments were used, such as laser ablation inductively coupled plasma mass spectrometry, Fourier transform infrared spectrometer, ultraviolet visible spectrophotometer, and laser Raman spectrometer. The gemmological characteristics, chemical compositions and spectroscopy characteristics of 6 "recrystallized emerald" samples were tested. The inclusions of the samples include water-ripple pattern, gas-liquid two-phase inclusion, and healed cracks. The chemical composition of the sample is w(Al2O3)=18.48%~18.79%, w(SiO2)= 65.93%~66.19%, and w(Be)=49 700×10-6~50 700×10-6. The trace elements are rich in V and poor in Fe. The infrared spectra of the samples showed absorption peaks at 2 326, 5 102, 5 272, 5 456, 6 817, 7 143 cm-1 and a wide absorption band in the range of 4 000~3 400 cm-1, which indicates that the samples contain both type Ⅰ water and type Ⅱ water. The UV-Vis spectra of the samples showed absorption of Cr3+, Fe3+ and V3+in one category, and absorption of Cr3+ and V3+ in the other. Raman spectra of the samples showed the Be-O telescopic vibration (1 067 cm-1), deformation vibration of Si-O-Si (683 cm-1) and lattice vibration (321.5 cm-1). The results showed that the characteristics of the "recrystallized emeralds" accord with the characteristics of hydrothermal synthetic emeralds, and no evidence indicates natural genesis. The so-called "recrystallized emerald" is more a gimmick for businesses to attract customers. The "recrystallized emerald" should be correctly named as synthetic emerald.