Clay Mineral in Similar Variety of Chicken-Blood Stone

In recent years, jade variety produced in Xi'an, Guizhou, Yunnan, Sichuan and other places with similar appearance to chicken-blood stone have appeared in the gem market. The "blood" colour part of those similar variety of chicken-blood stone is cinnabar and the main mineral components of base ("di") are quartz and carbonate minerals (calcite and dolomite).In this study, in order to analyze the mineral component, infrared spectra, and micro-morphology, selected representative samples of the similar varieties of chicken-blood stones were studied by using X-ray powder diffraction spectrometer (XRD), infrared spectrometer (IR), and scanning electron microscopy (SEM). Test results show that in addition to the cinnabar, quartz and carbonate mineral, those similar varieties of chicken-blood stones also contain trace amount of clay minerals, including illite, chlorite, and kaolinite.The functional area of infrared spectra shows the absorption peak of clay mineral caused by OH vibration. According to the SEM testing results, the small scaly illite was observed in the sample from Xi'an. Trace amount of clay minerals in the similar varieties of chicken-blood stone may be formed by the small amount of silicate minerals rich in aluminum which exist in early mineralization, and were metasomatized by low-temperature hydrothermal fluids or weathered. Because there are clay minerals in the similar species of chicken-blood stones, the identification of chicken-blood stone can not simply depend on whether it contains clay minerals.