DOI: https://doi.org/10.53036/2025-3-4(121-122)-2
Gemological studies of galliumgadolinium garnet with a color change effect
Gemological studies of galliumgadolinium garnet with a color change effect
| Yu. Gayevsky State Gemmological Centre of Ukraine |
| Yu. Ladzhun State Gemmological Centre of Ukraine |
| Language: Ukrainian |
| Precious and Decorative Stones. No. 3–4 (121–122), 2025: 19–21 |
| Abstract The experts of the SGСU conducted a comprehensive gemological examination of a sample of purple raw material. It was established that it is galliumgadolinium garnet with a color change effect (GIA, 1995, pp. 127–128). The purpose of the gemological study is a comprehensive study of a purple cylindrical stone in the form of raw material. Determination of its main gemological characteristics Galliumgadolinium garnet is an artificial product. This stone is not included in the Law of Ukraine “On State Regulation of the Extraction, Production and Use of Precious Metals and Precious Stones and Control of Operations with Them”. The characteristic features of the object of study were established: the optical nature of the stone, refractive indices, maximum birefringence, density, pleochroism, and the nature of fluorescence in the longwave (365 nm) and short wave (254 nm) ranges. Studies by semiquantitative Xray fluorescence analysis (EXDRF) showed a small amount of Nd oxide impurity. When studying the stone using a prismatic spectroscope, the Nd dye was determined in the absorption spectrum. Also, the phenomenon of color change was detected in this sample. Microscopic examination of the internal inclusions of the stone allowed to establish rounded and linearly directed gas bubbles. According to literature, this sample was grown using the Czochralski method. |
| Keywords: gadolinium gallium garnet, complex gemological research, microscopy, X-ray fluorescence analysis. |
| References |
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Gia. (1995). Gem reference guide. Gemological institute of america, 127–128. Quinn, e. P. (2004). Color-change glass, imitating alexandrite. Gems & Gemology, 40(1), 73–74 |