Feasibility Study on Color Grading of Blue Iolite Based on GemDialogue Color Comparison Charts

Abstract

To explore the feasibility of applying the GemDialogue color comparison charts to the color grading of blue iolite, the color of the charts was quantified by the integrating sphere handheld spectroscopy in this paper, and the screened data were classified into a total of 9 categories using the elbow rule and K-Means clustering analysis. Using Fisher’s discriminant to perform discriminant analysis on the 9 categories that have been classified, the discriminant function equation was established separately to verify the accuracy of this classification. Finally, the color parameters of iolite samples were substituted into the discriminant formula to obtain the color grade. By combining the classification results and visual observation, it is clear that applying the GemDialogue color charts to blue iolite color grading is feasible.