Abstract: Hemimorphite is a rare variety of jade.Hemimorphite with sky blue colour is of good quality.It has specific gravity of 3.34~3.46 g/cm³, refractive index of 1.60~1.62 and hardness of 4~4.5.T he main component is hemimorphite, and some carbonate such as smithsonite in small amount; Chemical composition analysis by microprobe shows that its colour is related to the content of CuO.Based on its colour and transparency, the quality of hemimorphite can be divided into four grades.