Acta Petrologica et Mineralogica

Yunxiao is a significant producing area of gem-quality garnet in China. However, the color origin of garnet in this area remains ambiguous, which restricts the understanding of their formation mechanism and subsequent exploitation. In this paper, 7 samples of orange-yellow-orange-red garnet from Yunxiao, Fujian were selected, and the spectral characteristics of the samples were analyzed by Fourier infrared spectrum, UV-visible spectrum and Raman spectrum, and the characteristics of main and trace elements were defined by electron probe (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis. It is concluded that the color of the garnet is predominantly influenced by the absorption of visible light by Mn²⁺ and Fe²⁺. Mn²⁺ dictates the yellow tone of the garnet, while a minor amount of Fe²⁺ governs the orange-red tone. Additionally, a trace amount of Ti⁴⁺ imparts a brownish appearance to the garnet. The samples exhibited a relatively low manganese content and high iron and magnesium content in their core, a gradual increase in manganese content from the core to the rim. The samples also displayed a left-leaning partition pattern, with an enrichment of heavy rare earth elements and a deficit of light rare earth elements. Europium (Eu) showed a negative anomaly. These findings suggest that the garnets from Yunxiao, Fujian were formed during magmatic processes and are products of late-stage magmatic crystallization.

garnet; gemological characteristics; mineral spectroscopy; color mechanism; Yunxiao, Fujian Province