玛纳斯碧玉致色离子对绿色参数的影响

摘要

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 cor-relation between the categories and contents of color-causing Ions and the green color pa-rameters-,C* and ho .The result shows that Manas Jasper mainly consists of microcrys-talline 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 con-text of 180 ~ 1000ppm,hue angle ho gets smaller and the yellow tint gets slightly im-proved,which makes the green color of the jasper more pretty for visual effect.Ni2 + and Mn2 + decrease the L* and ho of the green color which makes the green color greyish with mixed hues,causing color quality reduction.%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 Colori5测色仪,基于CIE1976L*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；Ni2+、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。