基于便携式地物光谱仪的常见宝玉石材质反射率光谱特征分析

SPECTRAL CHARACTERISTICS ANALYSIS OF COMMON PRECIOUS JADE MATERIAL REFLECTANCE BASED ON PORTABLE GROUND OBJECT SPECTROMETER

以傅里叶红外光谱与拉曼光谱为代表的宝玉石光谱分析法,虽然广泛应用,但仪器便携性有一定局限,难以对大体积或依附于金属类、纺织品类文物上的宝玉石进行原位无损检测。高光谱技术来源于卫星遥感,在地面实验中可以分为不成像的便携式地物光谱仪和图谱合一的高光谱成像仪。本研究采用便携式地物光谱仪对十余种宝石,包含透闪石、堇青石等无机盐类宝石,红宝石、蓝宝石等氧化物宝石,琥珀、蜜蜡等有机宝石进行观测,并对三类宝玉石的光谱特征进行了分析总结,得到以下结论:大部分无机盐类宝玉石均存在吸附水、羟基或者是羟基与阳离子的结合水光谱特征,且在2 000~2 400 nm有各自的特征基团的特征吸收峰;氧化物宝石在400~1 100 nm含有大量阳离子特征;有机宝石吸收特征峰以有机键氨基的倍频、组合频特征为主,是与前两类无机宝石区分的主要依据。研究表明高光谱分析能够准确鉴别出不同种类的宝玉石材质,在宝玉石类文物的快速无损鉴别、品质、产地分析等方面有较大潜力。

Although Fourier infrared spectroscopy and Raman spectroscopy are widely used,the portability of the instrument is limited to some extent.It is difficult to conduct nondestructive testing of precious jade with large volume or attached to metal or textile cultural relics.Hyperspectral technology originates from satellite remote sensing,which can be divided into portable ground object spectrometer without imaging and hyperspectral imager with integrated map in ground experiments.In this study,a portable ground object spectrometer is used to observe more than ten kinds of precious stones,including inorganic salt gems such as tremolite and cordierite,oxide gems such as ruby and sapphire,and organic gems such as amber and beeswax.The spectral characteristics of these three kinds of precious stones are analyzed and summarized,and the following conclusions are drawn-Most of the inorganic gems have the absorption characteristics of water,hydroxyl or the combination of hydroxyl and cation,and have their own characteristic absorption peaks from 2000 to 2400 nm.Oxide gems at 400 to 1100 nm contain a lot of cationic characteristics.The absorption characteristic peaks of organic gems are mainly the frequency multiplier and frequency combination of organic bond amino group,which is the main basis to distinguish organic gems from the above two kinds of inorganic gems.The test results by portable ground object spectrometer show that hyperspectral analysis can accurately identify different types of precious jade,and has great potential in the rapid and nondestructive analysis of precious jade,cultural relics and the analysis of the quality and origin of precious jade.