天然与染色“羽皇金”Akoya珍珠的宝石学及谱学特征  

Gemmological and Spetral Characteristics of Natural and Treated Yellow Akoya Pearl

作　　者：陈彩云飞 朱毅杰 吴静怡 周武邦 陈月罕宝 严雪俊 严俊 CHEN Caiyunfei;ZHU Yijie;WU Jingyi;ZHOU Wubang;CHEN Yuehanbao;YAN Xuejun;YAN Jun(Zhejiang Fangyuan Test Group Co.,Ltd.,Hangzhou 310013,China)

机构地区：[1]浙江方圆检测集团股份有限公司,浙江杭州310013

出　　处：《宝石和宝石学杂志（中英文）》2024年第4期49-58,共10页Journal of Gems & Gemmology

基　　金：浙江方圆检测集团股份有限公司自立科研项目(ZL202312)。

摘　　要：近两年,一类具有高饱和度及高明度色彩特征的黄色Akoya珍珠风靡我国珍珠市场,被冠以“羽皇金”的美称,其出现填补了8 mm以下小直径金黄色珍珠的市场需求,销量与日俱增。目前关于此类珍珠的宝石学及谱学特征的研究鲜有报道。本文对75颗黄色Akoya珍珠样品进行了表面特征观察、紫外-可见光光谱和光致发光光谱测试。结果表明:(1)天然黄色Akoya珍珠样品的表面纹理细腻,在长波紫外光下基本无荧光。部分染黄色珍珠样品的表面瑕疵处可见明显的晕斑,并具有不均匀的黄色、强蓝白荧光;(2)紫外-可见光吸收光谱测试结果表明,天然黄色Akoya珍珠样品可出现360~420 nm范围的吸收宽带及430~470 nm范围的吸收窄带,部分天然黄色-橙色珍珠样品可见类似尿卟啉结构的致色物质产生的405 nm处窄吸收带。染色珍珠样品在蓝紫区有较宽的吸收带,低于400 nm的强吸收带推测由增光剂所致;(3)光致发光光谱测试结果表明,天然黄色珍珠样品的荧光背景强度与文石主峰高度的比值(F/A)集中于1左右,大部分染色珍珠样品的F/A比值均在10以上。漂白增光处理后的珍珠样品的PL谱可产生575 nm和610 nm处的发光峰,染色珍珠样品则可能出现630~650 nm范围内的发光峰,增光剂和染剂发生联结增强发光体平面刚性,使得575 nm处的发光峰强度显著增强至湮灭630~650 nm间的染色剂信息。In recent years,highly saturated yellow Akoya pearls fill the market demand for golden pearls that less than 8 mm,and the sales volume increases rapidly.However,little researches have been done on the gemmological and spectroscopic characteristics of such pearls.In this paper,the gemmological characteristics,UV-Vis spectrum and photoluminescence spectrum of 75 pieces of Akoya pearls of light-yellow to golden colour were obtained.The result shows(1)The natural coloured yellow Akoya pearls has a delicate surface texture and almost no fluorescence under long-wave ultraviolet excitation.Some colour-treated samples show obvious iridescence circle at surface blemish.The uneven fluorescence in yellow or strong bluish white indicates the reagents penetrated.(2)UV-Vis spectrum shows that natural yellow Akoya pearls may exhibit 360-420 nm absorption broad band and 430-470 nm narrow band,and some natural pearl samples with yellow to orange colour show narrow absorption band at 405 nm generated by pigment that have similar structure to uroporphyrin.Colour-treated samples show broader absorption band at violet-blue range,and the strong absorption band below 400 nm may be caused by optical brighten agents.(3)PL spectrum shows that the ratio between fluorescence background intensity and the main aragonite peak(F/A)of naturally coloured samples clustered around 1.Most of the colour treated samples have F/A value above 10.Optical brightening agent treated pearl showed fluorescence maximum at 575 nm and 610 nm.The dyed pearl might show fluorescence information between 630-650 nm.The optical brighteners and dyestuffs might bond and increase the plane rigidity of luminophore,and the intensity of 575 nm might significantly increase to annihilate the dyestuff fluorescence information between 630-650 nm.

关 键 词：黄色Akoya珍珠 染色处理 紫外-可见光光谱 光致发光光谱 

分 类 号：O433.3[机械工程—光学工程] TS93[理学—光学]