Hyriopsis cumingii is chosen as the pearly mussel.The gemmological characteristics of the northern pearl produced from Liaoning Province of China were investigated,with the help of hydrostatic weighing method,X-ray powder diffraction,Fourier transform infrared spectroscopy and scanning electron microscope.The testing results show that the relative density of the northern pearl of China is from 2.722 1-2.733 5.The mineral components of the northern pearl of China are aragonite and protein.The structure of th...