Abstract:

Guatemala is the second largest producing area of feicui after Myanmar. The demand for the identification of feicui from the two origin areas is becoming more and more urgent, which is of great significance. The mineral composition, texture and structure characteristics of Guatemalan blue water jade were obtained by microscope observation, electron microprobe test and back-scattered electron images (BSE). Combined with the data of the tectonic environment, natural geographical environment, rough stone characteristics, and mineral composition characteristics of feicui from the two producing areas, a comparative analysis was made. The results show that compared with Myanmar jade, the weathered crust of the Guatemalan feicui is less rounded but thinner, with less granular tactile sensation, and little or almost no “red fog” from the skin inward. On the other hand, there are significant spherical weathering characters in the rough stones of Myanmar, the weathering crust is usually well rounded, thicker, and gritty to the touch. “Red fog” can be occasionally seen between the weathering crust and jade of the Myanmar feicui. The discriminant diagram of jadeite and omphacite composition shows the jadeite and omphacite from Guatemala appear relatively rich in Ca, and poor in Na, while the jadeite and omphacite from Myanmar are relatively poor in Ca, rich in Na. In terms of Fe content, the jadeite in the Guatemalan feicui is lower than that in the Myanmar feicui, while the omphacite in the Guatemalan feicui is higher than that in the Myanmar feicui. It can be used to distinguish the origin of feicui in actual production by comparing the appearance characteristics of feicui fully and analyzing the discriminant map comprehensively.

Key words: feicui, Guatemala, jadeite, omphacite, identification of origin