In this study, seventeen faceted gem-quality chrysoberyls exhibiting an attractive canary yellow color were investigated using a variety of gemological, spectral, and chemical methods. Microscopic observation revealed the presence of distinct growth lines and inclusions, including CO₂ fluids, carbon, and crystals of mineral such as calcite, quartz, sillimanite, and mica, identified by the Raman spectrum. The FTIR spectra showed the characteristic peaks of 2405 and 2160 cm⁻¹ and a 3223 cm⁻¹ peak in all samples, which can be accompanied by the 3112 cm⁻¹ shoulder, 3301, and 3412 and 3432 cm⁻¹ peaks. The UV-Vis spectra showed an Fe-related peak at 440 nm, along with the 650–660 nm band and the absorption band in the blue zone of visible light. Chemical analyses via EDXRF showed a composition poor in V and Cr and rich in Fe. The spectral and chemical results could help explain the origin of the canary yellow color, which originates from the abundant amount of Fe with very little influence from Cr and V.

This article reports on the recent mining and production status of ruby in Longido, Tanzania. Faceted-grade rubies and their matrix from Longido Area, Tanzania, were investigated by standard gemological testing, including FTIR, UV-VIS, Raman spectra, and LA-ICP-MS. Microscopic observations revealed dense needle-like and triangular inclusions, distinct growth lines, and color banding as typical inclusions. In agreement with the Raman results, the transmission FTIR spectrum confirmed the presence of aluminum hydroxide. The Raman spectra identified associated minerals and inclusions, including zoisite, parasites, feldspar within the matrix, rutile, and diaspore in the ruby host. The chemistry analysis revealed a high amount of Cr and relatively low iron as a good indicator of geographic origin.

In this study, seventeen faceted gem-quality chrysoberyls exhibiting an attractive canary yellow color were investigated by a series of gemological, spectral, and chemical methods. Microscopic observation reveals distinct growth lines and inclusions, including CO2 fluids, carbon, and mineral crystals such as calcite, quartz, sillimanite, and mica, identified by the Raman spectrum. The FTIR spectrum exhibits the 2405 and 2160 cm-1 feature peaks and a 3223 cm-1 peak in all samples, which can be accompanied by the 3112 cm-1 shoulder, 3301, and 3412 and 3432 cm-1 peaks. The UV-Vis spectrum shows a Fe-related peak at 440 nm, along with the 650–660 nm band and the absorption band in the blue zone of the visible light. The chemical results of EDXRF reveal a V-poor, Cr-poor, and Fe-rich feature. The spectral and chemical results could contribute to explaining the origin of the canary yellow color, which originates from the abundant amount of Fe with very little influence from Cr or V.