蓝色蓝晶石的宝石学特征及颜色成因探讨

Research on the Gemological Characteristics of Blue Kyanite and Its Color Contributing Factors

蓝晶石,又叫做二硬石,属于硅酸盐类矿物,是一种耐火度高的天然耐火原料矿物,工业用途非常广泛,但是较少人知道蓝晶石还有非常可观的宝石学价值。选取了6块蓝色依次加深的蓝晶石样品,对它的宝石学特征进行了研究,并采用了傅里叶红外光谱仪、紫外-可见光分光光度计、电子探针等大型仪器对样品进行测试,重点分析了它的颜色成因。研究表明,蓝色蓝晶石在350nm^400nm(紫区)及540nm^650nm(绿区-红区)这两个范围内均有吸收带,随着蓝色调的加深,蓝晶石在紫区的吸收程度变弱,在绿区至红区的吸收程度变强。蓝晶石样品中的主要致色元素为Fe、Ni,Fe离子含量越高,蓝色越深,反之颜色越浅。

Kyanite, also known as the two-hardness rock, which belongs to the silicate minerals, is a natural refractory minerals with high refractoriness. It has been widely used in industry, while few people knows that it has considerable gemological value. In order to study its gemological characteristics, 6 kyanite samples with blue color deepening in order have been selected to analyze its color contributing factors by large equipments such as Fourier infrared spectrometer, ultraviolet-visible spectrophotometer and EPMA. Result shows that blue kyanite has absorption band within both of the two ranges, 350nm-400nm （purple area） and 540nm-650nm （green-red area）. With the blue color deepens, the absorption degree of kyanite drops, while the absorption degree become strong from green to red area. The main color contributing elements of Kyanite are Fe and Ni. The blue color deepens as Fe content increases, the blue color becomes lighter the other way round.