钙长石质玉中钙铬榴石的谱学研究

所研究钙长石质玉中的绿色矿物是以钙铬榴石为主的石榴石，钙铬榴石在天然条件下非常稀有，颜色为翠绿色，品质高的钙铬榴石可与翡翠、祖母绿相媲美。前人对石榴石系列的其他端元矿物具有较为充分的研究，但对钙铬榴石的研究较少，且未见对钙长石质玉中钙铬榴石光谱特征的相关报道。使用JXA-8230电子探针确定样品石榴石平均组分为Uvt_49.66Grs_36.04Adr_13.58Pr_p0.67Sps_0.06，为以钙铬榴石为主的钙系石榴石。经Bruker Senterra R200L拉曼光谱仪测定样品拉曼位移为1 000，890，879，830，618，589，530，508，399，370，270，240和176 cm-1，受不同三价阳离子Cr3+，Al3+和Fe3+替代的相互影响而发生相应的偏移；用Bruker Vertex80红外光谱仪测定样品红外振动频率为1 019，951，908，844，826，721，669，608，538，496，462，430和413 cm-1，受不同组分晶胞体积及三价阳离子的质量分数影响，发生规律性振动偏移；通过Jasco MSV-5200显微紫外-可见光谱仪及近红外分光光度计测定样品，可见区Cr3+宽吸收带为439和613nm，存在453和685 nm吸收肩峰，同时可见Fe3+ 371 nm吸收肩峰，钙铬榴石主要致色离子为Cr3+。钙长石质玉中钙铬榴石的详细谱学研究为稀有钙铬榴石矿物的鉴定提供了丰富的谱学数据，为相似品独山玉进行区分奠定基础。

Spectra Characterization of the Uvarovite in Anorthitic Jade

The green minerals in Anorthitic Jade were considered to be uvarovite, which is a very rare member in natural garnet group. Uvarovite is very rare in natural conditions, the color is emerald green, uvarovite of high quality can be compared with Jade and Emerald. Predecessors have done some researches on the other end members of the garnets. However, little researches have been done on the uvarovite, no reports have been obtained about the spectrum characteristics of the uvarovite in Anorthitic Jade. The composition of this garnet was Uvt_49.66Grs_36.04Adr_13.58Pr_p0.67Sps_0.06 by using the JXA-8230 Electron Probe. Using the Bruker R200L Raman spectrometer, the Raman shifts we got of the sample were 1 000，890，879，830，618，589，530，508，399，370，270，240 and 176 cm-1，respectively, which have been influenced by the interaction of different trivalent cations Cr3+, Al3+ and Fe3+; Measurement of the infrared vibration frequency was performed using the Bruker V80 infrared spectrometer, acquiring the results of 1 019, 951, 908, 844, 826, 721, 669, 608, 538, 496, 462, 430 and 413 cm-1，respectively, the regular vibration excursion occurs due to the influence of the unit cell volume and the mass fraction of the trivalent cations; With the Jasco MSV-5200, the Micro-UV-Vis-NIR spectra shows that absorption peaks caused by electron transition of Cr3+were at 439, 613, 453 and 685 nm absorption were acromion, while a acromion absorption peaks caused by electron transition of Fe3+ was at 371 nm, the colored ion of the uvarovite is mainly Cr3+. The detailed spectrum study of the uvarovite in Anorthitic Jade provides rich spectral data for the identification of the garnet, and distinguishing from the similar traditional Dushan jade.