玛纳斯碧玉致色离子对绿色参数的影响

Influence of Color-causing Ion of Manas Jasper on Green Color Parameters

利用LA-ICP-MS、红外光谱、激光拉曼光谱等大型仪器对玛纳斯碧玉标本进行化学组成分析,并结合X-Rite Color i5测色仪,基于CIE1976 L＊a＊b＊均匀色空间量化碧玉绿色,探讨致色离子种类及含量与绿色参数L＊、C＊和ho的关系。结果表明,玛纳斯碧玉主要由微晶透闪石和阳起石组成,铁、铬、镍、锰等过渡金属元素含量高,其中Fe2＋对碧玉低彩度绿色（C＊值主要为5.0~8.50）起主导作用,含量越大,L＊、C＊均呈现减小的趋势,绿色越浓暗;而Cr3＋含量在（180~1000）×10-6范围内增大,色调角ho减小,黄色调略微提升,碧玉绿色更显俏丽而利于视觉效果;Ni 2＋、Mn2＋的存在降低了绿色的L＊、ho,使绿色灰暗且带杂色调,导致颜色质量下降。

Chemical composition analysis of Manas Jasper samples has been conducted through large equipments such as LA-ICP-MS,infrared spectrometer and laser Raman spectrometer.X-Rite Color i5 colour photometer has also been used to probe into the correlation between the categories and contents of color-causing Ions and the green color parameters-,C＊and ho.The result shows that Manas Jasper mainly consists of microcrystalline tremolite and actinolite with high content of transition metals such as Fe,Cr,Ni and Mn etc.Among them,Fe2＋dominates the low chroma green（C＊is mainly for 5.00~8.50）.When the content of Fe2＋increases,both of L＊and C＊show a decreasing trend and the green color becomes darker.With the increasing content of Cr3＋in the context of180~1000ppm,hue angle ho gets smaller and the yellow tint gets slightly improved,which makes the green color of the jasper more pretty for visual effect.Ni 2＋and Mn2＋decrease the L＊and ho of the green color which makes the green color greyish with mixed hues,causing color quality reduction.