蓝紫色堇青石的宝石学特征及颜色成因

Gemological Characteristics and Color Origin of Blue-violet Iolite

堇青石,又称之为水蓝宝石,是一种硅酸盐矿物,因其优良的性能,被广泛用于工业领域,但是高品质堇青石也被认为是稀少的宝石品种。针对珠宝市场上出现的蓝紫色堇青石,采用常规宝石仪器,红外光谱仪、紫外-可见分光光度计、X射线荧光能谱仪等对其宝石学特征、谱学特征和化学成分以及颜色成因进行研究。测试结果表明,红外光谱在676cm^-1、617cm^-1、580cm^-1处的吸收峰是堇青石特征吸收峰。堇青石在350~450nm之间有多条弱的吸收带,在500~650nm之间有宽的吸收带。随着颜色加深,500~650nm之间吸收带的吸收更强烈。蓝紫色堇青石的颜色成因主要和Fe元素含量有关,Fe元素含量越高,堇青石颜色越明显,反之亦然。

Iolite,known as aqua sapphire,is a silicate mineral that is widely used in the industrial field with its excellent properties,but high-quality iolite is also considered as a rare gemstone.For the blue-purple iolite in the jewelry market,the gemological characteristics,spectral characteristics,chemical composition and color genesis were studied by conventional gemstone instruments,infrared spectrometer,ultraviolet-visible spectrophotometer,and X-ray fluorescence spectrometer.The test results showed that the absorption peak of infrared spectrum at 676cm^-1,617cm^-1,580cm^-1 was the characteristic absorption peak of iolite.Iolite had a plurality of weak absorption bands between 350~450 nm,and a wide absorption band between 500~650 nm.As the color deepens,the absorption band between 500~650 nm was getting more strong.The color of blue-violet iolite was mainly related to the content of Fe.The higher the content of Fe was,the more obvious the color of iolite,and vice versa.