Structural Characteristics of Turquoise Filled with Aluminum Phosphate Adhesive

The quality grade, gemology characteristics, cutting and grinding processing of the loosen turquoises filled with aluminum phosphate adhesive are improved distinctly, and consequently they are similar with the natural turquoises. They can not be identified easily by gemmology testing methods. In order to verify the structure of this kind of modified turquoises and discuss the mechanism of the turquoises improved by the aluminium phosphate inorganic adhesive, the environmental scanning electron microscope (ESEM), thermogravimetric and thermal analysis (TG-DSC), infrared spectrum (IR) and X-ray powder diffraction (XRD) have been used to study the structural characteristics, phase, and thermal property of the turquoises filled with aluminum phosphate adhesive. It is indicated that the micro-pores of the turquoises after treatment are completely filled by aluminum phosphate adhesive as gelatinous, and the mineral composition and molecular structure of turquoises show no noticeable changes, but is amorphous in a degree. The amorphous structure is relevant with the filling of aluminum phosphate that is the inorganic polymer network structure forms when the aluminum phosphate adhesive is dehydrated. Moreover, the endothermic and exothermic reaction temperatures of the turquoises after treatment fall in certain degree than the natural ones caused by the addition of aluminum phosphate.