“黑青”“黑碧”的谱学鉴别特征探究

Study on the Spectral Identification Characteristics of“Heiqing”and“Heibi”

“黑青”指颜色近黑色,主要成分为透闪石的青玉。“黑碧”指颜色近黑色,主要成分为阳起石的碧玉。采用电子探针、激光剥蚀电感耦合等离子体质谱仪和红外光谱测试分析手段,确定“黑青”“黑碧”的矿物种属。采用拉曼光谱、显微紫外-可见分光光度计、红外光谱对“黑青”“黑碧”的谱学鉴别特征进行探究。“黑青”为标准透闪石拉曼谱峰,“黑碧”的谱峰位置与“黑青”存在几个波数的偏差,向波数小的方向移动。可见-近红外波段,“黑青”出现445 nm吸收峰,680和940 nm宽吸收带,为Fe^2+和Fe^3+作用;“黑碧”出现445 nm吸收峰,660和690 nm双吸收峰以及970 nm吸收峰,为Fe^2+,Fe^3+,Cr^3+作用。显微紫外-可见光谱可分析到样品的近红外区,“黑青”在1397,2310,2387和2466 nm出现强吸收峰,1915和2120 nm出现弱吸收峰;“黑碧”在1400,2313和2394 nm出现吸收峰。红外光谱分析“黑青”在5225,4738,4692,5349,4317,4190和4064 cm^-1存在吸收峰;“黑碧”在4708,4307,4178和4031 cm^-1存在吸收峰。显微紫外-可见光谱与红外光谱分析结果虽然存在小的差异,但基本保持一致,以红外光谱分析结果为准。将透闪石质的“黑青”、阳起石质的“黑碧”、广西大化阳起石质玉进行对比,综合红外光谱和显微紫外-可见光谱分析结果得出“黑青”(透闪石)与“黑碧”(阳起石)近红外光谱的鉴别特征:“黑青”(透闪石)在4800~4600 cm-1存在两个吸收峰,4350~4300 cm^-1存在分裂双吸收峰;“黑碧”(阳起石)在4800~4600 cm^-1存在一个弱吸收峰,4350~4300 cm^-1存在一个吸收单峰。且“黑碧”(阳起石)的近红外吸收峰相较于“黑青”(透闪石)整体向低波数方向移动。

"Heiqing"refers to dolomite-related nephrite with the color of the nearly black whose main component is tremolite."Heibi"refers to serpentinite-related nephrite with the color of the nearly black whose main component is actinolite.EPMA,LA-ICP-MS and FTIR spectrum were applied to obtain the mineral species of"Heiqing"and"Heibi".Raman spectrum,Micro-UV-Visible spectrophotometer and FTIR spectrum were used to investigate the spectral identification characteristics of"Heiqing"and"Heibi"."Heiqing"have the standard tremolite peak position,and main peak positions of"Heibi"have several wavenumber deviations,which move in the direction of small wavenumber.In visible-near infrared band"Heiqing"appear 445 nm absorption peak and 680,940 nm wide absorption band,which were attributed to the role of Fe^2+ and Fe^3+;"Heibi"appears 445 nm absorption peak,660,690 nm double absorption peak and 970 nm,which were attributed to the role of Fe^2+ and Fe^3+,Cr^3+.The near-infrared region of the samples can be analyzed by Micro-UV-Visible spectrophotometer.The strong absorption peaks of"Heiqing"appear at 1397,2310,2387 and 2466 nm,and the weak absorption peaks appear 1915 and 2120 nm;The absorption peaks of"Heibi"appear at 1400,2313 and 2394 nm.The results of FTIR spectrum indicates that the absorption peaks of"Heiqing"were at 5225,4738,4692,4349,4317,4190,4064 cm^-1 and the absorption peaks of"Heibi"were at 4708,4307,4178 and 4031 cm^-1.Although there aresome small differences between the results of Microscopic UV-Visible spectrum and FTTR spectrum analysis,the results are basically consistent,the results of FTIR spectrum analysis shall prevail.By comparing"Heiqing","Heibi"and actinolite jade of Dahua,the near-infrared spectrum identification characteristics of"Heiqing"(tremolite)and"Heibi"(actinolite)are"Heiqing"(Tremolite)have two absorption peaks at 4800~4600 cm^-1,and split double absorption peaks at 4350~4300 cm^-1."Heibi"(actinolite)have a weak absorption peak at 4800~4600 cm^-1,and a single absorption peak at 4350~4300 cm^-1.Moreover,the whole near-infrared absorption peaks of"Heibi"(actinolite)moves in the direction of smaller wavenumber than"Heiqing"(Tremolite).