The Effect of Munsell Neutral Value Scale on the Color of Yellow Jadeite and Comparison between AP and K-Means Clustering Color Grading Schemes

Ziyuan Liu,Ying Guo

doi:10.3390/cryst12020241

Abstract

Yellow jadeite is a kind of jadeite caused by secondary leaches. With a certain degree of transparency, its color is usually influenced by the objective conditions including light source and background. In this paper, 19 Munsell neutral value scales were selected to study the impact caused by background under the standard light source D65, where we found that the N9.5 Value Scale is suitable for color grading. All 33 yellow jadeites were tested by UV-VIS spectrophotometer and colorimetric analysis, and the colors were graded by the affinity propagation (AP) and K-means clustering methods. According to the result, the yellow jadeite color was classified into Fancy, Fancy Intense, Fancy Deep, and Fancy Light. It is also concluded that AP is more feasible to provide the color grading scheme, while K-means can be applied to the optimization of choosing clustering center.

Highlights

Jadeite is a beautiful polycrystalline jade, of which those of gem-quality are mostly produced in Burma and Guatemala [1,2,3,4]
TDhueeEtofftehcet torfan1s9paMreunncysealnldNcehuatrraactleVrisatliuceabSscoarlpetsioonnoYf tehleloywellJoawdejiatdeeite, the testing backgDrouuendtos athnde tlirgahntsspoaurrceenwcyoualnddmcahkaeraacsitgenriifisctiacntabinsflourepntcieononotfhtehceolyoer.llIonwoujardeite, t ing backgrounds and light source would make a significant influence on the color previous study, we have discussed the impact of the different light sources on jade
Under the standard D65 light source, the background has a significant impact on the color of yellow jadeite

Summary

Introduction

Jadeite is a beautiful polycrystalline jade, of which those of gem-quality are mostly produced in Burma and Guatemala [1,2,3,4]. It is loved by the Chinese for its versatile color. The least weathered part is grayish-green, and its color-causing mineral is thought to be chlorite, while yellow and red jadeite receive a higher degree of weathering, the main crack filler is limonite colloid (hematite, goethite), and the most intense weathering of the surface layer showing black [7,8]

Methods

Results

Conclusion