Construction Of Quality Evaluation System Of "Taishan Jade"

As a new type of jade,the quality evaluation system of Taishan jade needs to be established urgently.Referring to the national standards and local standards of gemstone/jade,starting from the definition and classification of"Taishan jade",this thesis tests and objectively evaluates its luster,transparence,clarity and color.Based on the experiments of Fourier transform infrared spectrometer,Raman spectrometer,Electron Probe Micro-analyzer and X-ray Fluorescence Spectrometer,the standard spectrums are given,and the definition of Taishan jade is defined clearly:The cryptocrystalline jade,which is produced in the West foot of Mount Tai and mainly composed of antigorite,often contains inclusions such as chromite,magnetite,heazlewoodite,pentlandite and pyrrhotite,and Taishan jade is different from serpentine jade from other places because of its high content of Ni and Cr.According to the characteristics of color,transparence and structure,it can be divided into four categories:Taishan BiYu,Taishan MoYu,Taishan HuaBanYu and Taishan Yellow jade.In addition,those with commercial name of"HuaBan marble"are mainly composed of albite,which cannot be classified as Taishan jade.The gloss test is carried out by using the UG 60plus glossmeter.According to glossiness and image clarity,luster can be divided into excellent（A）,medium（B）and poor（C）.The samples were tested by UV-Vis spectrophotometer,and then the unit transmittance was calculated.With 40%,30%and 20%as the boundary,the grades are transparent（T₁）,translucent（T₂）,slightly transparent（T₃）,opaque（T₄）.Considering the fracture,inhomogeneous structure and mineral inclusions,Using Python program to calculate the proportion of inclusion area,and the clarity is divided into four levels:pure（A）,relatively pure（B）,general（C）,and impure（D）.The color of Taishan jade was measured by X-Rite SP62 integral sphere spectrophotometer（reflection）and color i7800 color difference analyzer（transmission）,and use Color Standard Album of China（CSC）for color match.Through the test and comparison,it is considered that there is no need to characterize and evaluate the color of Taishan MoYu;the reflection method can be used to characterize and evaluate the color of Taishan light BiYu;and the reflection method and color matching method can be used to characterize and evaluate the color of Taishan light HuaBbanYu.After analysis,the color classification boundary is determined and the corresponding CSC color number is given;the transmission method can be used to characterize and evaluate the color of Taishan BiYu and Taishan yellow jade.The theoretical uniformity of the Chinese color system is good,but the actual chip is not very reductive to the system.It is suggested to correct or cancel the color chips with large deviation.In view of the limited quantity and quality of the samples,only the Taishan BiYu was classified systematically.from low to high,the color level was light green-yellow,green-yellow,light yellowish-green,yellowish-green,dark green and green.It was stipulated that the color"deep sea green"range of the highest commercial level of Taishan BiYu.In this paper,the quality evaluation system of Taishan jade is preliminarily constructed,and the detailed classification basis of Taishan BiYu is given with emphasis.Various methods of color test and characterization are innovated,which provides reference for quality classification of Taishan jade in the future.