Zhejiang Zhuji Freshwater Pearl And Shell Structure And Its Powder Identification

China is known as the inventor of the pearl farming method, with a history of morethan 900 years. In the past a few decades, pearl farming has witnessed a gorgeouslyrapid development in China that majority pearls are produced therefrom, especiallypearl powder, one of the most important and expensive Chinese traditional medicines.Large quantities of fake commodities such as pearl nacre powder, nacre mother ofpearl powder are also seen in the market, which makes the study on how to identifythem very important and necessary.In the paper, various freshwater cultured pearls, mainly from Zhejiang, have beenused for the studying of the pearl powder, pearl nacre powder and pearl mother ofpearl powder. The research covers the following:1.Gemmological microscope, petrological microscope and Scanning ElectronMicroscope are used in observing the sections of various pearls to investigate thestructure features of various pearls and pearl producing shells such as Hyriopsiscumingii. There are differences between the structure of Chinese freshwater culturedpearls and seawater cultured pearls. Freshwater cultured anuclear pearls are notsimple concentric rings of nacre layers. Between the nucleus and the nacre layers,there is prismatic calcite layer in seawater nucleated pearl, but not in freshwaternucleated pearl.2.Pearls of different quality have been studied concluding that the quality of pearl isrelated with the structure of nacre layers of the pearl. Such factors as thickness ofsingle nacre layer affect the luster and iridescence effect greatly.3.The origin of internal structure of nacre layers is further validated through plenty ofobservations.4.The transect of pearl powder and pearl nacre powder are is sandwich but nacremother of pearl powder's shape is like pole or fiber.5.To differentiate pearl powder,pearl nacre powder and nacre mother of pearlpowder by applying thermodynamics.The dissertation is theoretically important for developing gemology of cultured pearls.the understanding of the genetic relationship between the quality of cultured pearlsand their structure and composition resulting in developing high-efficiency and highquality pearl farming technique and the studying of pearl powder and other powderprotecting the consumers' rights.