Abstract: The high-quality green Feicui materials from Guatemala appearing in the market are primarily composed of omphacite minerals, with secondary minerals including phlogopite, phengite, zoisite and aegerine. Omphacite can be classified into three different formation stages, Omp-Ⅰ, Ⅱ, andⅢ, with Omp-Ⅲbeing the main part of high-quality green Feicui from Guatemala. Omp-Ⅰ is mostly residual structures of metasomatism; Omp-Ⅱ is mostly embedded in a mosaic structure, which is entirely embedded in the residual cracks of the early omphacite and formed through metasomatism; Omp-Ⅲ is mostly a fiber interwoven structure, with some metasomatic relationship between its edges and early omphacite. Omp-Ⅲ has bright colours and delicate structure. In terms of composition, high-quality Feicui from Guatemala has the characteristics of being rich in Fe and Cr elements compared to green jadeite from Myanmar. The endmember compositions and mineralogical characteristics show significant differences compared to Myanmar's high green jadeite. This can provide important mineralogical typological references for effectively distinguishing high-quality Guatemalan green Feicui from traditional green Feicui in Myanmar.