Gemmological and Mineralogical Characteristics of A New Kind of Marble Jade from Shanxi Province

A new kind of marble jade with mainly two colours, yellow and yellowish-brown, is found in Liuleng Mountain in the north of Shanxi Province.It is a kind of high-quality facing stone and jade carving material with compact structure and good transparency.The gemmological and mineralogical characteristics of the marble jade samples are studied by using the slice observation, environmental scanning electron microscopy, X-ray powder diffraction, LA-ICP-MS and conventional gemmological methods.The results show that the jade is a kind of marble transformed by metamorphism, in which the content of CaCO₃is between 96%and 97%.And probably, it is Fe that determines its colour.Furthermore, trace amounts of carbon and iron powders obstruct the recrystallization process of columnar calcite, resulting in the perthitic texture.And the calcite column, proved to be irregular xenoblastic texture, is irregular polygon cylinder.By analyzing the jade’s structure features, this paper concludes that the marble jade product possesses the advantages of smooth surface, strong luster and being not easy to be broken when it is cut in parallel to the stripe direction.