Fig. 1. Color of yellow sapphire samples showing in “fading state” (a) and “coloring state” (b)

Fig. 2. Samples present discoid (HS-1) and pinnate (HS-2) inclusions indicating dissilient tracks caused by heat treatment

Fig. 3. UV-Vis spectrum of 13 samples

Fig. 4. UV-Vis spectrum of some samples in “coloring state” and “fading state”

Fig. 5. 3D fluorescence spectrum of S-2 and S-0 in “fading state” and “coloring state”