莫桑比克摩根石的谱学特征研究

近几年摩根石凭借它独特的色彩悄然兴起。采用常规仪器测试、激光剥蚀等离子质谱(LA-ICP-MS)、紫外-可见吸收光谱(UV)、红外光谱(IR)和拉曼光谱(Raman)，对产自莫桑比克的摩根石基本性质、化学成分特征、谱学性质进行了较为详细的分析。紫外-可见光谱获得样品主波长、饱和度、明度等相关颜色参数;成分测试显示样品摩根石中Li，Rb，Cs，Mn等含量较高，计算所得到的晶体化学式为Be_3.2090Al_2.0757Li_0.425Si_5.664O₁₈(Na_0.1420Cs_0.1316);红外光谱显示，摩根石的结构振动区主要在指纹区400～1 200 cm-1，其中900～1 200 cm-1为Si—O—Si环的振动区，550～900 cm-1为Be—O振动区，而450~530 cm-1为Al—O振动区。由于摩根石中的Cs元素的含量较高，而Cs为原子序数较高的元素，其存在可能令Si—O—Si环振动谱峰向低频位移。拉曼光谱显示1 065 cm-1为Si—O非桥氧伸缩面内振动，1 000 cm-1左右为Be—O的非桥氧伸缩面外振动，685 cm-1为Si—O—Si的变形面内振动，400 cm-1为O—Be—O的面外弯曲振动，在390 cm-1处为Al—O的面外变形振动，在320 cm-1处为Al—O的面外弯曲振动。

Spectroscopic Characteristics Study of Morganite from Mozambique

In recent years, morganite is becoming more and more popular due to its special color. The morganite samples located in the Republic of Mozambique were detailedly analyzed for its basic properties, chemical composition characteristics and spectroscopy properties by laser ablation plasma mass spectrometry (LA-ICP-MS), ultraviolet-visible absorption spectra (UV-Vis-NIR), infrared spectrum (IR) and Raman spectroscopy. The color parameters of morganite samples including the main wavelength, saturation, and lightness were got by UV-Vis-NIR. Chemical composition test showed higher content of Li, Rb, Cs and Mn in samples and chemical formula was calculated as Be_{3.209 0}Al_{2.075 7}Li_0.425Si_5.664O₁₈(Na_{0.142 0}Cs_{0.131 6}). Infrared spectroscopy showed that morganite structure vibration area is mainly in the fingerprint area 400～1 200 and 900~1 200 cm-1 for the vibration of the ring Si—O—Si, 550~900 cm-1 for Be-O vibration area, and 450~530 cm-1 for Al—O vibration area. Because the Cs element content is higher in sample morganite and Cs belongs to higher atomic number elements, its existence may move the vibration frequency of Si—O—Si rings to the low position. Raman spectra showed 1 065 cm-1 for Si—O inner vibration of non bridge oxygen, around 1 000 cm-1 for Be—O outer vibration of non bridge oxygen, 685 cm-1 for Si—O—Si inner vibration of deformation, 400 cm-1 for O—Be—O outer vibration of bending, 390 cm-1 for Al—O outer vibration of deformation, 320 cm-1 for Al—O outer vibration of bending.