Discussion of Colour Origin in Amazonite

Based on the literatures, we studied gemmological characteristics of five amazonite samples, and conducted in-depth research with the help of advanced instrumentation. The contents of trace elements (Fe,Rb and Pb) were obtained by laser ablation inductively coupled plasma mass specrtrometry (LA-ICP-MS). We identified structural water and liquid water among 3 800~3 200 cm^-1 using microscopic FTIR spectroscopy. We found three strong absorption centers at 380、625 nm and 740 nm by using microscopic UV-Vis spectrophotometer. Comparing the results from heat treatment and irradiation treatment, we concluded that the hole-related centers at 380, 640 nm and 725 nm caused its colour. The colour has no direct relation with the structural water.