The Quantitative Characterization And The Impact Factors Of Synthetic Blue Spinel

The spinel, particularly the natural candite which often serves as the alternatives ofaquamarine and sapphire in gem-set jewellery, always enjoys a great popularity for itslively colors and luster. However, due to the limited varieties of the natural candite,the synthetic candite which is the most common variety of the synthetic spinel, holdsa greater share in the market and is widely applied to the fashion items such asjewelry and finery as well as industrial products such as fire proof materials andnanophase materials. With the improvement of the synthesis technique and theincreasing personal and industrial needs, it has proved to be essential to identify thecolor parameters of the synthetic spinel in a way that is accurately enough.In this paper, the color parameters of110synthetic candites were measured in the D65standard illuminant by using the Color i5and the color parameters of all the syntheticcandites were quantified based on the CIE1976L*a*b*uniform color space. Then thecontents of trace elements in the samples were tested by LA-ICP-MS; then adiscussion and analysis was carried out about the correlations among color parametersand the quantitative relationship between the color-causing ion Co²⁺of the syntheticcandites and their corresponding color parameters with the method of the SPSS partialcorrelation analysis.The conclusion is as follows: when the influence of the saturationand the hue angle on the chromatism is controlled, the luminosity equation has agreater impact on the chromatism with the correlation coefficient of0.897; thesaturation of the hue, though working as an important factor determining the color ofthe candite, it contributed less to the perception of the color blue by the naked eyesthan the lightness. The Co²⁺of the synthetic candite enjoys the closest linearrelationship with the lightness, meanwhile, by controlling the influence of the hue andthe chroma on the lightness, the liner relationship between the content of Co²⁺and thelightness, with the correlation coefficient of0.989, is closer than its relationships withthe saturation and the hue angle.Through analysis of the lustrousness and the colorparameters of the synthetic candites of varied surface smoothness, the means of thesamples of the synthetic candites decreased from42.24to35.81according to thedegradation of the surface smoothness, suggesting a relatively sharp deline. But as thesurface smoothness continue to decline, the lustrousness tended to decline slower thanbefore. The lustrousness of the synthetic candites holds a less significant impact onthe hue of color but quite a direct impact on the saturation and the lightness, with therelative rote of change of40.49%and11.8%. Additionally, when the syntheticcandites enjoy less thickness, the lightness of the samples would improve while thesaturation would decline, with the relative rote of change of12.9%and23.78%.This paper studied the relationship between the color-causing ion Co²⁺and the threeelements of the color of the synthetic candites, and the imfluence of the lustrousnesson the color, in order to apply the result of the study into practice, such as improvingthe colour and luster of the synthetic candite as well as the techenique of syntheticcandite production.