Gem Color Determination: From Visual Analysis to Instrumental Evaluation

The features and problems of gem evaluation using “color” as a quality indicator that arise with the control method and the use of the existing GIA, State Registry of Measuring Instruments of the Russian Federation, and World of Color color classifiers are examined. A digital color classifier built on the principles of the Mansell atlas is proposed. The proposed classifier is intended for use in automated devices for instrumental evaluation of the color of gems. Using the example of the scale of green hues of color, the possibility of creating a system of digital standards corresponding to the colorimetric standards of the International Commission on Illumination (CIE) is shown. Requirements are presented for automated devices for instrumental evaluation of gem color.