gems, jade, jadeite, fei cui, Guatemala jadeite, fei cui, imperial jade

High-grade green jadeite jade samples from Guatemala were selected as the research objects. Gem microscope, polarizing microscope, microscopic laser Raman spectrometer, and electron probe microanalyser were used to analyze the appearance characteristics, magnification features, constituent minerals, microstructures, Raman spectra, and mineral chemical compositions of the samples. Based on constituent minerals and their evolution, three periods of mineralization were observed. The product of the early mineralization period is jadeite with coarse-grained, hypautomorphic–automorphic granular-columnar texture and very pure chemical composition. The main mineralization period is characterized by metasomatism, with earlier-stage products being fine-grained jadeite containing relatively higher FeO, Cr₂O₃, MgO, and CaO contents compared to jadeite from the early period, and later-stage products being fine-grained omphacite with high MgO and CaO contents, whose green color shades correspond to Cr₂O₃ variation. The late mineralization period products consist of jadeite (or albite) + titanite in a filling texture, with titanite mainly distributed in reticulated veins between jadeite/omphacite particles or in microfractures. The combination of jadeite (or albite) + titanite + fluid inclusions formed during this late stage appears as white cotton-like zones in jadeite jade, representing fluid-melt inclusions. The fluid phase in these inclusions contains CO₂ and CO, with a strong characteristic Raman shift peak at 2,145 cm⁻¹, indicating a highly reductive formation environment with high CO content, corroborated by the presence of amorphous carbon in the samples. Jadeite is the main or one of the main minerals in most of the high-grade Guatemalan green jadeite jade samples studied. In such samples, the late-stage assemblage of jadeite + reticulated titanite + CO-dominated fluid inclusions commonly found in white “cotton” areas serves as an important reference feature for distinguishing Guatemalan high-grade green jadeite jades from Burmese green jadeite jades.