Gemmological and Mineralogical Characteristics of “Beige Jade”

A kind of mineral occurs in Yunxian,Hubei province,naming "Beige jade" by its colour appearance.It is known as its delicate quality and pure colour.The mineralogical,gemmological and spectral characteristics of six "Beige jade" samples are studied by means of the conventional gemmological methods,the slice observation,infrared spectrometer,XRD and LA-ICP-MS.The results indicate that the structure of "Beige jade" samples is in mosaic arrangement of short prismatic crystals with its size in the range of 0.240—0.880 mm in length and 0.064—0.160 mm in width,showing the orientate arrangement.The main chemical compositions of the samples are CaCO₃,containing a small number of MgCO₃ and less impurity.According to GB/T 16552—2003 GemsNomenclature,the gem-quality "Beige jade" should be directly named as "marble" and explained as "popular name:'Beige jade'" in the notes.