Fig. 1. Samples of turquoises
(a): Natural turquoise; (b): Treated turquoise

Fig. 2. Fluorescence characteristics of natural turquoise samples

Fig. 3. Fluorescence characteristics of soaking and filling treatment turquoi sesamples

Fig. 4. Infrared absorption spectrum of turquoise

Fig. 5. Peaks in the fluorescence spectrum of natural turquoise

Fig. 6. Peaks in the fluorescence spectrum of soaking treatment turquoises

Fig. 7. Peaks in the fluorescence spectrum of filling treatment turquoises