桂林龙胜红色系“贵妃料”鸡血玉的矿物学特征及其颜色成因

Mineralogical Characteristics and Coloration of the Red Series'Guifeiliao'Chicken Blood Jade in Longsheng,Guilin

桂林“龙胜鸡血玉”为一种新兴的石英质玉石,商业上称玉化程度好的品种为“贵妃料”鸡血玉。本文以不同红色系(呈现不同色调的粉色、粉紫、红色)“贵妃料”鸡血玉为研究对象,采用常规宝石学仪器、偏光显微镜、电子探针、X射线荧光光谱仪、电感耦合等离子体质谱仪及紫外-可见光谱现代测试技术,对其矿物学特征及其颜色成因进行研究。结果表明“贵妃料”鸡血玉主要由粒度大约为60μm石英颗粒组成,占总含量约86%以上。放大观察下粉色和红色“贵妃料”含有可致色的赤铁矿、针铁矿以及无定形水合氧化铁。粉色“贵妃料”中赤铁矿仅以粉尘状形式存在,其含量小于0.5%;红色“贵妃料”样品中赤铁矿以粉尘状、鳞片状、浸染状形式存在,含量约为0.5%~1%,随含量的增加鸡血玉的颜色越红。此外,紫外-可见光吸收光谱的分析结果进一步表明,粉色“贵妃料”还受到Mn离子的影响,碳酸盐为Mn离子主要赋存矿物;粉紫色鸡血玉中几乎不含致色矿物,推测与杂质元素Fe^(3+)引起的空穴色心[FeO_(4)]^(4-)有关。

Guilin Longsheng Chicken Blood Jade is a new type of quartz jade.Commercially,the variety with good jadeization degree is'Guifeiliao'Chicken Blood Jade.In this paper,different red series(pink,pink purple and red with different hues)'Guifeiliao'Chicken Blood Jade were used as the research object.The mineralogical characteristics and color genesis of the jade were studied by using conventional gemological instruments,polarizing microscope,electron probe,X-ray fluorescence spectrometer,inductively coupled plasma mass spectrometer and ultraviolet-visible spectroscopy.The results show that the'Guifeiliao'Chicken Blood Jade is mainly composed of quartz particles with a particle size of about 60μm,accounting for more than 86%of the total content.Under enlarged observation,pink and red princess'Guifeiliao'contain colorable hematite,goethite and amorphous hydrated iron oxide.Hematite in pink'Guifeiliao'only exists in the form of dust,and its content is less than 0.5%.The hematite in the red'Guifeiliao'sample exists in the form of dust,scaly and disseminated,and the content is about 0.5%-1%.With the increase of the content,the color of the Chicken Blood Jade is redder.In addition,the analysis results of ultraviolet-visible absorption spectroscopy further indicate that the pink'Guifeiliao'is also affected by Mn ions,and carbonate is the main mineral of Mn ions.Pink purple Chicken Blood Jade almost does not contain coloring minerals,which is speculated to be related to impurity elements.