Imitation gemstone glass has numerous characteristics, including low cost, rich colour, stable colouring, and the formation of colour-changing effects that can meet the jewellery market demand for beautiful gemstones of middle and low grades. In this study, four types of gem-imitating glass were prepared by the elemental substitution of praseodymium, neodymium and chromium elements based on rare earth glass and examined by combining refractive index, density, spectral characteristics and colour parameters. Sample 1 contained only Pr6O11 and showed a golden-yellow colour like chrysoberyl. Sample 2 contained only Nd2O3 and showed a blue-purple colour like amethyst. Sample 3 contained Pr6O11 and Nd2O3 and appeared green under D65 light source and red under A light source, with a colour-change effect like alexandrite. Sample 4 contained Pr6O11, Nd2O3 and Cr2O3 and showed a highly saturated green colour like emerald because of the strong colouring effect of Cr3+ in the glass. The findings revealed that all four samples are transparent, with a refractive index greater than 1.5 and a density higher than 2.6 g/cm3. The comprehensive performance of the four imitation gemstone glasses can be found in the corresponding natural gemstones, which has a certain practical value.
Keywords: colour change effect; gem-imitation; praseodymium-neodymium-chromium; rare earth glass; spectral characteristics.