The Characteristics Of The Crust Of Myanmar Jadeite Jade And The Relationship With Internal Jade

The good quality of Jadeite jade in the world mainly originates from Myanmar.The Jadeite jade deposits in Myanmar can be divided into primary and secondary deposits according to their geological occurrences and origin.The primary deposit jade stone after water transport and accumulation of formation of secondary deposit,secondary deposit Jadeite jade stone in different environment has a rich and colorful crusts.In this thesis 8 pieces of Myanmar Jadeite jade were selected which have different crust,by means of gemological test,observation under the gemological microscope and polarizing microscope,XRD,EPMA,FTIR,DTA,and combined with the previous research,to investigate the relationship between the Jadeite jade crust and internal jade in the structure and composition.In this thesis gemological test,gemological microscope and polarizing microscope observation are carried out to analyze the structure characteristics of the Myanmar Jadeite jade crust and internal jade.Jadeite jade from crust to inside has inheritance in particle size.There is no significant difference of the particle size of two parts.Compared to the part of the inside,the mineral of crust automorphic extent is higher,commonly seen fragmentation phenomenon.From the microscopic image contrast between the crust and inside,there are more open fracture and unknown dark granulated substance in the crusts.The content of bulk material from crust to inside showed a decreasing trend.The structure of crust is loose,and the particle clearance is large.The iron dip-dye phenomenon happens along the open fissures,particle clearance,cleavage fracture.Compared to the crust,the inside metamorphic crystallization particles are more intense,the indirect fuzzy part is closely connected to the dentate.The transparency of Jadeite jade is related to the size of mineral particles,the degree of crystallization of mineral particles and the orientation of mineral particles.The difference of crust and inside transparency and gloss is mainly caused by structural difference.The XRD,EPMA,FTIR,DTA are performed to analyzed the composition characteristics of the Myanmar Jadeite jade crust and internal jade.Jadeite jade is mainly composed of jadeite,pyroxene,amphibole and feldspar minerals.Despite different crust of jadeite jade and the inside has different appearance,the EPMA test showed jade stone from the crust to inside composition is relatively uniform.Compared with the internal jade,the crust forms a small amount of clay minerals and colloids.With the physical weathering of jadeite original rock,weathering products in Jadeite clastic rock deposit near the residual part of the crust.Jadeite mineral particles dissolved substances in water and organic acid(such as Ca²⁺,Mg²⁺,Fe²⁺),forming carbonate,and in the form of true solution to migration.Insoluble material in the form of colloidal mineral particles exists in clearance and the original rock surface,forming limonite,gibbsite,kaolinite and chlorite at different redox conditions.