Gemological Characteristics of Nephrite Jade from Huanren, Liaoning

By using routine gemological testing, thin section observation under microscope, Fourier Transform Infrared (FTIR) Spectrometric analysis and the chemical analysis method, a systematic study of nephrite jade from Huanren has been investigated for minerals, chemical compositions and gemological characteristics. The results indicate a refraction index of 1.60, specific density of 3.08 and Mohs hardness of about 6.5. Thin section observation by polarizing microscope show that the main mineral composition is of epidote and hornblende and the impurity minerals are diopside, apatite, carbonate minerals and serpentine among others. The main textures of the jade are inequigranular blastic, foliated pilotaxitic and metasomatic. The specific texture characteristics of the nephrite are responsible for its poor transparency, uneven color distribution, and the inclusions of black spots and green agglomerate. The features of the infrared spectra are very similar to those of standard reference tremolite which indicate that the jade is indeed nephrite. The chemical analysis results were similar to Hetian′s jade and Xiuyan′s nephrite jade. The impurities of hornblende (biotitization) affected the quality of the jade.