Identification Characteristics of Imitated Black Nephrite Gravel Composite Stone

The price of nephrite gravel is becoming higher and higher due to the growing market demand，and more and more imitations are produced.By means of gemmological microscope，polarizing microscope，X－ray powder diffraction and Fourier transform infrared spectrometer，an imitated black nephrite gravel composite stone，which is found in Wuhan Xudong Antique and Jewelry Market，is identified in terms of gemmological，mineralogical and spectral characteristics.The results show that the material is mainly made up of three parts：the black nephelinite，the white tremolite and black organic glue.The differences of the identification characteristics between the imitated and natural black nephrite gravel are that the cross section of the former has obvious signs of composite stone and characteristic infrared spectra organic absorption peak.