Mineralogical Study of Turquoise Reconstructed with Aluminum Phosphate Adhesive

The small particles of the wasted turquoises improved to a larger monomer scale and a higher quality jewelry grade by the way of pressing reconstruction are treated with the Al(H₂PO₄)₃ adhesive whose chemical compositions are similar to that of turquoise.In order to study the structure of this kind of modified turquoises and discuss the mechanism of the turquoises improved by the Al(H₂PO₄)₃ adhesive,the gemmological characteristics and the structural characteristics of this kind of turquoise samples before and after the treatment are tested and analysed by using the environmental scanning electron microscope,infrared spectrum,X-ray powder diffraction and chemical composition analysis.The results show that the micro-pores of the turquoise samples after the treatment are filled by Al(H₂PO₄)₃ adhesive as gelatinous,and some microcrystals are dissolved with weak recrystallization reaction.The mineral components and molecular structure of the turquoise samples have no noticeable change,but the growth of the microcrystal net plane(120) of turquoise is promoted by the addition of Al(H₂PO₄)₃ adhesive.