Title: “Ice Jade” from Guatemala
Source: Gems & Gemology
Authors: Zhaoying Huang, Tao Chen, Jinyu Zheng, and Zebin Xu
Published: Spring 2024, Vol. 60, No. 1
Link: https://www.gia.edu/gems-gemology/spring-2024-ice-jade
Abstract:
“Ice jade” is a translucent variety of jadeite jade (also known asfei cui) that is generally of high value. Reportedly from the Morales mine in the Izabal Department of Guatemala, it has recently appeared in the Chinese jewelry market. In this study, the structural characteristics, mineral compositions, and color genesis of Guatemalan “ice jade” were studied using scanning electron microscopy, cathodoluminescence, X-ray diffraction, electron probe microanalysis, Raman spectroscopy, and ultraviolet/visible/near-infrared spectroscopy. “Ice jade” is composed almost exclusively of jadeite, with accessory minerals that include omphacite and albite. The chemical composition of the samples studied here was nearly pure sodium pyroxene. A small amount of fine-grained omphacite imparted a pale green color to this material. This “ice jade” exhibited fine-grained texture, occasionally with some micro-granular texture. Guatemalan “ice jade” has a unique characteristic appearance, microstructure, accessory minerals, and chemical compositions, but further study is needed to distinguish it from the other origins.
Jadeite jade, also called fei cui in China, is the most popular jade variety and one of the best-selling gems in China. Color and transparency are the primary quality factors that determine value. Jadeite jade is a polycrystalline aggregate, primarily consisting of jadeite (NaAlSi2O6) and including accessory minerals such as omphacite, albite, amphibole, and chromite (Harlow and Sorensen, 2005; Yuan, 2009). Gem-quality material is only found in a few countries, namely Myanmar, Guatemala, Russia, Kazakhstan, and Japan (Tsujimori and Harlow, 2012; Coccato et al., 2014; Abduriyim et al., 2017). Myanmar is the traditional and most important producer of gem-quality jadeite jade, while Guatemala has become the second-largest producer (Zhang and Shi, 2022).
From the thirteenth century to the early twenty-first century, the jadeite jade sold in China came exclusively from Myanmar (Hughes et al., 2000; Zhang, 2003). The use of jadeite jade in Central America can be traced back to 1500 BCE, but the specific source was not identified until more recently. In 1952, Robert Leslie, a researcher at the Smithsonian Institution, first found detrital nodules of jadeite in Guatemala (Foshag and Leslie, 1955). Over the next 50 years, geologists and locals discovered more jadeite mines there. After 2000, small amounts of Guatemalan material began to enter the Chinese market (Zhang, 2003). The mineral composition of different varieties of Guatemalan jadeite varies greatly. According to its main composition, it can be divided into three categories: jadeite jade, omphacite jade, and jadeite-omphacite jade. The major mineral of these three categories is jadeite, omphacite, and mixed-phase jadeite-omphacite, respectively (McClure, 2012; Lin et al., 2020). The color range of Guatemalan jadeite jade includes light to medium green, white, purple, and blue (Hargett, 1990; Abduriyim et al., 2017; Ouyang et al., 2017; Spring 2024 Gem News International, pp. 97–99). The Guatemalan jadeite jade initially sold in the Chinese market was coarsely grained and not transparent enough to be considered gem quality. Consequently, Guatemala was thought to produce low-quality material. But that has changed recently, as vivid green semitransparent as well as pale green translucent jadeite jade from Guatemala has entered the Chinese market (Wang et al., 2022).
In the Chinese market, nearly colorless jadeite with fine texture and high transparency is called “ice jade.” A Guatemalan variety with a near-transparent appearance (figure 1) is called “white water jade” by Chinese sellers. This material is usually near-colorless with pale gray-green or pale gray-blue colors and often contains some white snowflake-shaped impurities. It has a fine texture, and the highest-value specimens are transparent. This article studies the gemological properties, textural characteristics, and mineral compositions of fine-quality “ice jade” from the Morales mine in Guatemala and aims to provide evidence that distinguishes it from similar Burmese material.
