【摘要】 珍珠的颜色是影响其品质最关键因素之一。目前珍珠颜色的研究大多集中在不同颜色珍珠的组成元素、致色机理及结构差异，但对于如何直观分辨同种颜色珍珠的研究却很少。选用三批产自安徽不同时期的淡水养殖白色珍珠，对其进行色度学、激光拉曼光谱测试及宝石显微镜观察，建立白色系淡水养殖珍珠的白度值与拉曼光谱的关系并结合宝石显微镜的观察对其颜色等级的划分提供依据。运用亨特白度公式，W_HT=100-[（100-L^*）²+a^*2+b^*2]^1/2计算出不同珍珠样品的白度值，再与拉曼光谱中由C—C伸缩振动引起的1 132 cm^-1峰的峰面积和由[CO₃]^2-对称伸缩振动引起的文石峰面积的比值即R值进行对比发现，淡水养殖白色珍珠的白度值与拉曼光谱中的R值成反比。运用SPSS聚类分析对安徽产淡水养殖白色珍珠进行颜色分级，可将其白度值划分为85以上，85～80, 80～75和75以下四个区间，白度值在85以上为最白，85～80之间为较白，80～75之间为中等白度，75以下为最差。安徽产淡水养殖白色珍珠的表面形貌观察发现，白度值在85以上的珍珠表面较光滑且光泽度很强，白度值在85～80之间的珍珠表面有一部分缺陷但光泽度较强，白度值在80～75之间的珍珠则有较明显的缺陷光泽度也一般，而白度值在75以下的珍珠表面则缺陷较多且光泽度较差。珍珠表面的光滑度和光泽度会影响珍珠白度。白度值和拉曼光谱中R值的大小均可定量表示安徽产淡水养殖白色珍珠的洁白程度，两者之间存在一定的对应关系，即白度值越大，拉曼光谱中的R值越小，珍珠越白；珍珠表面的光滑度和光泽度可以作为评判珍珠洁白程度的辅助依据。综合利用淡水养殖白色珍珠的色度学参数和拉曼光谱，再结合显微结构观察对其洁白程度进行区分这也可以为淡水养殖白色珍珠颜色等级的划分提供理论依据。更多还原

【Abstract】 The color of the pearl is one of the most critical factors affecting its quality. At present, most researches on pearl’s color focus on the constituent elements, coloring mechanism and structural differences of different colors, but there are few studies on how to distinguish the pearl of the same color intuitively. In this paper, three batches of freshwater cultured white pearls from different periods in Anhui were selected and subjected to colorimetry, laser Raman spectroscopy and gemstone microscope observation. Based on this, the relationship between the whiteness value and Raman spectrum of white freshwater cultured pearls was established. Then combined with the observation of gemstone microscope, it provides the basis for the division of its color grade.This paper uses the Hunter whiteness formula, W_HT=100-[（100-L^*）²+a^*2+b^*2]^1/2 to calculate the whiteness value of different pearls, and then compares the whiteness value with the R value, which is the ratio of the peak area of the 1 132 cm^-1 caused by the C—C stretching vibration and the aragonite peak area caused by the symmetrical stretching vibration of the[CO₃]^2-. It is found that the whiteness value of the freshwater cultured white pearl is inversely proportional to the R value of Raman spectra. The cluster analysis in SPSS can be used to classify the colors of freshwater cultured white pearls from Anhui. By cluster analysis, the whiteness values can be divided into four ranges: above 85, 85～80, 80～75 and below 75. The whiteness value above 85 are the whitest, 85～80 are white, 80～75 are medium whiteness, 75 or less are the worst. By observing the surface morphology of Anhui freshwater cultured white pearls, it can be found that pearls with a whiteness value above 85 have a smoother surface and strong gloss. Pearls with a whiteness value between 85 and 80 have some defects, and strong gloss on the surface, pearls with a whiteness value between 80 and 75 have obvious defects and medium gloss, pearls with a whiteness value below 75 have more defects and poor gloss on the surface. The smoothness and gloss of pearls will affect the whiteness. Both the whiteness value and the R value of the Raman spectra can quantitatively indicate the whiteness of Anhui freshwater cultured white pearls. The relationship between them is that the larger the whiteness values are, the smaller R values in Raman spectrum are, and the whiter pearls are. The gloss and smoothness of pearls can be used as an auxiliary basis for judging the whiteness of pearls. The whiteness of freshwater cultured white pearls can be distinguished by coloration parameters, Raman spectra and microstructure observation. They can also provide a theoretical basis for the classification of the color grade of freshwater cultured white pearls.更多还原