Jadeite jade,also called Feicui in China,is the most popular jade variety and one of the best selling gems in China.Colour and transparency are the primary quality factors that determine the value of Feicui.Jadeite jade is a polycrystalline aggregate,primarily consisting of jadeite(NaAlSi2O6)and including accessory minerals such as omphacite,albite,amphi-bole,and chromite[1-2].Gem-quality Feicui material is only found in a few countries,namely Myanmar,Guatemala,Russia,Kazakhstan,and Japan[3-5].Myanmar is the traditional and most important producer of gem-quality jadeite jade,while Guatemala has become the sec-ond-largest producer[6]."Ice jade"is a translucent variety of jadeite jade(also known as Fei-cui)that is generally of high value.Reportedly from the Morales mine in the Izabal Depart-ment of Guatemala,it has recently appeared in the Chinese jewelry market.In this study,the structural characteristics,mineral compositions,and colour genesis of Guatemalan"ice jade"were studied using UV-Vis-NIR and Raman spectroscopy,X-ray diffraction,electron probe microanalysis,scanning electron microscopy,and cathodoluminescence."Ice jade"from the Morales mine in Guatemala is composed of almost pure jadeite,con-taining very small amounts of accessory minerals,including omphacite and albite.The om-phacite grains are often nearly colourless and not easily observed,while the albite grains cluster as white snowflake-like inclusions or dispersed as small specks.The"ice jade"exhib-its a fine-grained structure,occasionally coexisting with a micro-granular structure.The rel-atively pure chemical compositions of sodium pyroxene accompany with a fine texture pro-duced a transparent to semi-transparent and near-colourless appearance.A small amount of dispersed fine-grained omphacite is considered the cause of the pale green colour in"ice jade"from Guatemala.The Guatemalan origin can be determined from its characteristic appear-ance,microstructure,accessory minerals,and chemical compositions.
"ice jade"jadeitealbitetranslucentGuatemala
Tao Chen、Zhaoyin Huang、Jinyu Zheng、Zebin Xu
展开 >
Gemmological Institute,China University of Geosciences,Wuhan 430074,China
School of Earth Sciences,China University of Geosciences,Wuhan 430074,China
Guangdong Provincial Gem & Precious Metal Testing Centre,Jieyang 522000,China
NETL
NSTL
万方数据
