Development of artificial peridot gemstones from glass materials

Abstract

The aims of this research to develop artificial peridot gemstones from glass materials. Glass was prepared from the formula (40-x)SiO2: 10B2O3: 25Na2O: 8CaO: 5ZrO: 1Bi2O3: 0.5TiO2: 0.5Al2O3: 10BaO: xCr2O3 mol% where x is the concentration of Cr2O3 (0.00, 0.01, 0.02, 0.03, 0.04 and 0.05 mol%) have been synthesized by conventional melt quenching technique at 1,200 C for 3 hours. Studied the physical properties and the optical properties of glass The results showed that density and refractive index tends to increase according to the increasing concentration of Cr2O3 . The molar volume decreases with increasing concentration of Cr2O3. The absorption spectra of glass in the wavelength range of 200 to 1,100 nm showed absorption broadbands at 631 nm, caused by the energy level change in the ground state (4A2g(F)) to the excitation state 4T2g( F) , corresponding to absorption of orange- red light. Additionally, it is found that the absorption peak in the low- energy region of the electron transition spectrum shifts towards longer wavelengths with increasing concentration of Cr2O3. Color analysis in the CIE L* a* b* system showed that the illuminance ( L* ) was independent of the amount of Cr2O3 concentration added, with the a* value ranging from - 0. 3185 to - 23. 4073, and b* value ranging from 1. 3802 to 54. 9082. It was found that glass doped with Cr2O3 at 0.1 mol% had L* value of 89.0136, a* value of -10.1118, and b* value of 24.7183. The color value was close to that of real peridot in nature and have similar physical characteristics.