新疆于田和田玉的谱学特征及产地特征研究

新疆是世界重要和田玉产地之一，其中于田产和田玉又为优质山料的代表。研究对来自新疆于田县哈尼拉克、阿拉玛斯、赛迪库拉木、齐哈库勒四个矿点的48块和田玉样品进行谱学特征及化学成分分析，采用常规宝石学测试、傅里叶红外光谱、激光拉曼光谱以及激光剥蚀电感耦合等离子体质谱等现代谱学仪器测试。结果表明，新疆于田和田玉样品颜色呈青色、青白色、青黄色、黄白色、灰白色特征，样品呈典型油脂—玻璃光泽，不透明—半透明，为多晶质集合体，折射率在1.61～1.62范围，相对密度范围为2.95～2.99。新疆于田和田玉样品的红外光谱显示了900～1 200和400～760 cm-1范围内透闪石的特征吸收谱带。O—Si—O反伸缩振动、对称伸缩振动显示为位于1 143，1 096，1 040，995和925 cm-1处的峰，Si—O—Si对称伸缩振动显示为位于763和689 cm-1处的峰，而538，512，465和420 cm-1处的峰与Si—O弯曲振动、M—O的晶格振动及OH平动有关。新疆于田和田玉的拉曼光谱符合透闪石谱学特征，其中120，175，220，365和389 cm-1处是晶格振动峰值，670 cm-1峰值代表了闪石类矿物的Si—O—Si伸缩振动，931，1 029和1 060 cm-1是由于Si—O伸缩振动，3 672和3 680 cm-1属于M—OH伸缩振动。新疆于田和田玉的主要成分为MgO，CaO和SiO₂，稀土元素特征显示为δCe值为0.068～3.902，平均值1.064；δEu值为0～8.832，平均值0.343，具有负Eu异常；LREE/HREE为0.010～3.369，平均值0.682。ΣREE值为0.407～18.768，平均值3.138。利用微量元素特征和稀土元素特征可从化学成分方面将新疆于田和田玉与韩国春川、新疆且末、青海三岔河等其他代表性产地的和田玉进行区分。新疆于田和田玉的谱学特征及成分信息丰富了和田玉产地信息数据，为进一步研究提供参考，未来可以根据宝石学特征、谱学特征和稀土元素、微量元素特征提取各产地和田玉的产地信息，结合和田玉成矿地质条件背景，使和田玉产地精细溯源至每个矿点矿脉成为可能。

Study on Spectroscopy and Locality Characteristics of the Nephrites in Yutian,Xinjiang

Xinjiang is one of the important nephrites origins in the world, and primary nephrites from Yutian have a representative of high quality. 48 nephrites samples from Hanilake, Alamas, Saidikulamu and Qihakule were analyzed by conventional instrument testing, Fourier transforms infrared spectroscopy (FTIR), laser Raman spectroscopy and laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) analysis for the investigation of spectroscopic characteristics and chemical compositions. The result showed that nephrites from Yutian, Xingjiang varied from cyan, bluish white, bluish yellow, and yellowish white to gray. The samples are opaque to translucent with greasy to glass luster. As polycrystalline aggregates, nephrites had a variety of specific refractive indices(1.61～1.62) and gravity (2.95～2.99). Infrared spectroscopy spectra displayed the typical tremolite absorption between 900～1 200 and 400～760 cm-1. Infrared absorption bands at 1 143，1 096，1 040，995，925 cm-1 were induced by O—Si—O anti-symmetric stretching vibration and O—Si—O symmetric stretching vibration, 763，689 cm-1 were induced by Si—O—Si anti-symmetric stretching vibration, and 538，512，465，420 cm-1 were induced by Si—O bending vibration, M—O lattice vibration and OH horizontal vibration. Raman spectroscopy spectra of nephrites from Yutian, Xinjiang were consistent with the tremolite characteristics. 120, 175, 220, 365, 389 cm-1 were the lattice vibration peak, 670 cm-1 represented the Si—O—Si stretching vibration of amphibole minerals, 931, 1 029, 1 060 cm-1 were due to Si—O stretching vibration, 3 672, 3 680 cm-1 belongs to M—OH stretching vibration. The main components of Yutian nephrites are MgO, CaO and SiO₂, and rare earth element characteristics had ranges of 0.068 to 3.902 for δCe, 1.064 for average; δEu ranges from 0 to 8.832, 0.343 for average, with negative Eu anomaly. LREE/HREE ranges from 0.010 to 3.369, 0.682 for average. The ΣREE ranges from 0.407 to 18.768, 3.138 on average. Based on the characteristics of trace elements and rare earth elements, nephrite from Yutian, Xinjiang can be distinguished from other representative areas such as Chuncheon (Korea), Qiemo(Xinjiang) and Sanchahe(Qinghai). The spectroscopic characteristics and chemical compositions of nephrites from Yutian, Xinjiang have enriched the information and data of nephrites’ origin and provided a reference for further study. In the future, the origin information of nephrites from other producing areas can be extracted based on gemological characteristics, spectral characteristics, rare earth elements and trace elements. Combined with the background of ore-forming geological conditions, it is possible to trace the origin of nephrites to every vein.