Influence of Fe²⁺ on the Color Appearance of Yellow-Green Peridot

Abstract:

Twenty-eight yellow-green color of uniform, high clarity and similar thickness of 5 mm × 7 mm oval faceted peridots from Jiaohe Jilin province were examined by LA-ICP-MS and Color i5 to test their chemical compositions and L^*, C^* and ho. The correlations between Fe²⁺ and color parameters were analyzed, in order to establish the influence on the color appearance of Fe²⁺. The chemical formula of the twenty-eight peridots is (Mg_1.84,Fe_0.19)_2.04[(Si_0.982,Al_0.001)_0.983O₄], which was calculated by oxygen atom. It reveals that 0.19 mol Fe²⁺ is concluded in one mol peridot, and Fe²⁺ is the colorant of peridot. Based on the CIE 1976 L^*a^*b^* uniform color space, relationships between chromaticity coordinates a^*, b^* and chromaticity C^* were analyzed by Two-way ANOVA, of which the results showing that the influence of b^* on C^* (r_b*×C*=0.996) is much more prominent than a^* on C^* (r_a*×C* = -0.383). By partial correlation analysis of the results calculated through CIE LAB color-difference formula, it can be discovered that lightness difference DL^* has a better correlation with chromatic aberration DE^* than DC^* and DH^*, whereas the significance level ρDC*×DE* > 0.05, rDH*×DE* > 0.05, it reveals that DE^* is more sensitive to DL^*. At the same time, L^* changes the most with the contributions of Fe²⁺ compared with other parameters of peridot. It is concluded that, with the help of L^*, Fe²⁺ has a further influence on the color appearance of peridot.

• Periodical: Key Engineering Materials (Volume 492)
• Pages: 370-373
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.492.370
• Online since: September 2011
• Authors: Wei Xi Tang, Ying Guo, Li Xia Ma
• Keywords: Chromatic Aberration, Fe²⁺, Lightness, Peridot

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