Application of cluster analysis and discriminant analysis in quality grading of jadeite red

Abstract

A more effective grading standard for jadeite-jade red was established through combining gemology with statistics. 120 jadeite-jade (red) samples were tested by X-Rite SP62 integral spherical spectrophotometer under standard light source D65 to quantify the lightness (L∗), hue (hab°) and chroma (Cab∗) of jadeite-jade red based on CIE 1976 L∗a∗b∗ uniform color space theory. K-Means clustering analysis method in SPSS 22.0 statistical analysis software was used to grade the color of red jadeite-jade. Fisher discriminant analysis method was used to verify the feasibility of the classification and to find an objective and effective color grade evaluation method. Finally, the jadeite-jade red was divided into five grades: Fancy Vivid, Fancy Deep, Fancy Intense, Fancy dark and Fancy.