Study on Mineralogical Characteristics of Turquoise Samples from Different Provenances by Non-destructive Analysis

The application history and provenance of turquoise were summarized in this paper.Technologies including proton induced X-ray emission (PIXE),X-ray diffraction (XRD) and scanning electron microscope (SEM)were used to study the mineralogical characteristics of several turquoise samples from Iran,Hubei,Tibet and other places.The colorific mechanism was discussed based on the chemical components.The experimental results show that turquoise specimens with different qualities and from different provenances have different chemi- cal compositions,but the contents for their major components are identical.The color of turquoise depends on the content ratio of CuO and Fe_2O_3 and the color changes from sky-blue to green with the decrease of the w(CuO)/w(Fe_2O_3)ratio.