采用傅里叶变换红外光谱仪KBr粉末压片法和原物镜面反射法对 8件文石样品进行测试,对比了两种方法的差异.深入探讨文石晶体在不同方向上红外镜面反射光谱的变化,发现文石的红外镜面反射光谱具有显著的各向异性:在垂直、平行和斜交于文石 c轴的面上[CO3]2－产生的 v3振动反射峰宽化易出现变形和位移现象;v2振动反射峰峰位和相对强度发生明显的规律性变化.由此,认为红外镜面反射光谱可用于文石晶体取向的研究.在此基础上,对 5件养殖珍珠表面和剖面进行测试对比.结果显示,从养殖珍珠表面获得的红外镜面反射谱与文石垂直于 c轴的底面所得相同;养殖珍珠剖面上测得的红外镜面反射谱与文石平行/斜交于 c轴的面所得谱类似,于是推断养殖珍珠中文石晶体是以c轴指向球心的方式排列的.

8 pieces of aragonite samples were tested with Fourier transform infrared spectrometer KBr powder tabletting and spectral reflection method,and the differences between the two methods are compared.The differences of IR spectral reflection spectrum from aragonite crystals different directions are discussed emphatically,and the difference is very significant in the vertical,parallel and oblique c-axis of aragonite crystals.The reflection peak that made by [CO3]2－v3 widening will induce deformation and displacement;The peak position and relative strength of v2 significantly changes regularly.Thus,the spectral reflection IR spectrum can be used in test of aragonite crystal orientation.On this basis,the surface and section of 5 pearls are used to compare.The results show that the spectral reflection IR spectrum measure from the pearl surface is same to that from aragonite bottom surface which is perpendicular to the c-axis,and that from the pearl section is similar to that from the plane parallel or oblique aragonite c-axis.Then,we can conclude that the aragonite in pearls is arranged by the way of crystal c-axis pointing to its core.