Identification of “Insignificant-Filled” Turquoise

The price of turquoise keeps rising in recent years and a large number of fissure-filling treated turquoises appeared in Chinese gem market. The "insignificant-filling" is a common treated method for turquoises. In this paper, the author investigated the "insignificant-filled" turquoises by using gem microscopy, UV-Vis and FTIR techniques. The results showed that the purpose of "insignificant-filled" is reinforcing the fissures and veins of turquoise in order to improve the production rate of turquoise. Magnification observation with the FTIR peaks at 1 740-1 750 cm^-1 could proved the turquoise samples being "insignificant-filling". Based on the results in this paper, combining with the national standard GB/T16552-2017 Gems-Nomenclature on quantification of gems, the quantification system on the fissure-filling turquoise is stated. Four classes(grades) of the filling turquoise are N(None), L(Light), M(Moderate), S(Serious).