Abstract: In order to study the morphology,chemical composition,symbiotic relationship among major minerals and the typical embedding characteristics of the hydromagnesite from Bangor Lake in Tibet,polarizing microscope,scanning electron microscope,transmission electron microscope,electron probe and MLA mineral analysis system were used.The results indicate that the hydromagnesite is cryptocrystalline aggregate which consists of small crystal particles.The single crystal which has characteristic striation on the (001)is monoclinic plate-like.The hydromagnesite crystal usually grow into layered polysynthetic twin and contact twin along (100).Aragonite,dolomite and other carbonate minerals are often associated with hydromagnesite in disseminated symbiotic relationship in raw ores.It might be difficult to use physical mineral processing to get rid of them.