Fig. 1. Character of yellowish green beryl samples after heating-treatment at reducing condition

Fig. 2. Character of greenish yellow beryl samples after heating-treatment of oxidizing condition

Fig. 3. Comparison of IR spectra between natural and heated Beryl samples
(a): Natural sample b1; (b): Heated sample b5 (light-blue); (c): Heated sample b10 (light-blue)

Fig. 4. Comparison of UV-Vis spectra between natural and heated beryl samples
(a): b4; (b): b5; (c): b6; (d): b8; (e): b9; (f): 10

Fig. 5. Comparison of EPR spectra between natural and heated beryl samples
(a): The original spectrum of EPR; (b): The partial enlarged spectrum between 2 500~4 000 H (Gauss)