Abstract: In the paper, the gemmological characteristics of gem grade blue-green amazonite sample from Mozambique were tested by using the polarizing microscope, Raman spectrum, inductively coupled plasma mass spectrometer and environmental scanning electron microscopy.The result showed that the amazonite sample from Mozambique is primarily composed of potassium feldspar and albite.The blue-green part of amazonite is mainly composed of potassium feldspar and the white part is mainly composed of albite.Potassium feldspar and albite intergrowth together regularly.Based on the theory of modern gemmology colour formation,there are two main views about the colour cause of amazonite.(1) Rb and Cs elements take the place of K element, which form colour heart; (2) Pb element takes the place of K element which form colour heart.Though ICP-MS, we found that the content of Rb、Cs、Pb elements in the blue-green part and the white part of amazonite sample from Mozambique are different.The colour cause of amazonite sample from Mozambique was discussed that one or two elements of Rb、Cs、Pb take the place of K element which is such quality as alternative in the crystal structure of amazonite, leading to structural defects, forming colour heart.