中国云南蓝色碧玺的化学成分及谱学特征研究

Chemical Composition and Spectral Characteristic of Blue Tourmaline from Yunnan Province,China

云南怒江地区是中国迄今为止丰富的在产矿区,自1980年发现云南碧玺矿后开采至今,目前对云南碧玺全面的宝石学特征研究较少。本文选择云南福贡、贡山地区9颗蓝色碧玺样品为研究对象,并利用激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)对比已报道的其它若干处产地碧玺样品的主微量元素含量,总结出云南蓝色碧玺样品的产地特征及元素含量差异。结果显示,显微镜观察发现云南蓝色碧玺样品的内部存在管状及气液两相包裹体;拉曼光谱表明其还存在结构水,同时指出了Fe元素等金属阳离子含量对拉曼光谱的影响规律;红外光谱根据4339 cm^(-1)和4600 cm^(-1)处的特征峰,推断出云南蓝色碧样品的元素含量与吸收峰强度关系;紫外-可见吸收光谱分析表明,云南蓝色碧玺样品的蓝色调由Fe^(2+)-Fe^(3+)的价态迁和Mn^(2+)-Ti^(4+)的电荷转移造成。综上,鉴于碧玺晶体质量和颜色,中国云南地区是碧玺的一个优质产地。

Nujiang area of Yunnan Province is a rich mining area in China.Since the discovery of Yunnan tourmaline mine in 1980,it is still being mined today,and there has been little comprehensive gemmological researches on it.9 pieces of blue tourmaline samples from Fugong and Gongshan areas,Yunnan Province,China,have been tested by laser-ablation inductively coupled plasma mass spectrometry(LA-ICP-MS),and the contents of main and trace elements of the tested samples were compared with several reported samples of blue tourmalines from other origins.The results indicated that there are tubular and gas-liquid two-phase inclusions in the interior of the blue tourmaline samples by microscopic observation.Raman spectra showed that there is structural water in blue tourmaline samples,and the influence of metal cation content such as Fe element on Raman spectra was pointed out.Based on the characteristic peaks at 4339 cm^(-1) and 4600 cm^(-1),the relationship between element content and absorption peak intensity of blue tourmaline from Yunnan was deduced by infrared spectroscopy.Ultraviolet-Visible absorption spectrum analysis showed that the blue tourmaline samples from Yunnan were caused by valence transition of Fe^(2+)-Fe^(3+)and charge transfer of Mn^(2+)-Ti^(4+).In summary,in view of tourmaline crystal quality and colour,Yunnan,China,is a high-quality source of tourmaline.