Contrast Study Of Mineralogy On The Natural Turquoise And Treated Turquoise From Zhushanjiubei Province

Natural turquoises and treated turquoises from Zhushan,Hubei were studied in thisinvestigation. There was a research on mineralogical characteristics of natural turquoisesthrough the modern methods which contained EPMA,XRD,SEM,IR spectrum, Raman spectrum.Besides this, there also had a contrast study on natural turquoises and the treatments. The resultsas follows:The results of microscopic observations and XRD analysis revealed that the turquoises fromZhushan,Hubei were mainly composed of turquoise with small amounts of quartzs. They werecryptocrystalline structure,nodular and botryoidal structure in some local positions. The surfacemorphology observed by SEM showed crystals which were long board and columnar structureclearly in2000×. The boundaries of the crystals were clear, but random arrangement. Thechemical compositions of the turquoise from Zhushan,Hubei were near the theoretical valuefluctuations, w(Al2O3) varied between30%～38%,w(P2O5) between36%～39%,w(CuO)between7%～9%. The infrared spectrum and the Raman spectrum of the turquoises wereresulted mainly from the vibration mode and frequency of water, hydroxyl units and [PO4]tetrahedron. The [PO4] group in the fingerprint region were not only the ν3,ν4with infraredactivity, but also the ν1,ν2infrared inactive had been alive, showed a weak absorption bands at907,426cm-1. The ν1,ν2,ν3and ν4of the [PO4] were raman active in Raman spectroscopy.According to the characteristic absorption peaks, the water in turquoise had structure of water,water of crystallization and adsorbed water.The presence of wax absorption peak was detected in the wax-dipped turquoise by IRspectrum: CH2stretching vibration bands at2919cm-1and2851cm-1and CH2-CH3stretchingvibration bands at2882cm-1and2847cm-1in Raman spectrum. Both methods were detectedCH2-CH3bending vibration band at1466cm-1. However, the dull color and rubber residualwere observed in the surface of the polymers-impregnated turquoises, and they might beresponsible for the relatively low RI,SG and Hm value. The crystals of thepolymers-impregnated turquoises were not clear, and the polymer were between the particlesand the fractures. They were observed at2947cm-1,2860cm-1(CH2stretchingvibration),especially at1732cm-1(C=O stretching vibration) in IR spectrum and at the3011～2800cm-1(CH2-CH3stretching vibration) region in Raman spectrum. Both methods were detected CH2-CH3bending vibration band at1465cm-1. Concentrations of colored polymer andthe fallen color layer were visible on the dyed turquoise. The reconstructed turquoises hadgranular structure. The dyed and reconstructed turquoises were treated bypolymers-impregnated method at the same time,so the absorption peaks of polymer weredetected in IR spectrum and Raman spectrum.