Figures of the Article

• Sapphire samples (No. S1-S14)
• Apatite samples (No. A1-A12)
• Cordierite samples (No. C1-C12)
• CIE 1931 chromaticity diagram of three blue gemstone samples
• Point of three blue gemstone samples drapping at L a^*b^* 3D coordinates
• L a^*b^* projection points projecting on each of the three planes
• Point of three blue gemstone samples drapping at L Ch_ab^* 3D coordinates
• L Ch_ab^* projection points projecting on each of the three planes