合成彩色立方氧化锆的宝石学特征

市场上出现的紫色、浅紫色、浅黄色、粉红色、酒黄色、黄褐色、红色人造立方氧化锆均为亚金刚光泽, 火彩明显; 密度为5.99～6.34 g/cm3, 相对硬度为8～9; 除粉红色者表现出非均质性和弱多色性且内含大量定向排列的白色脱溶物外, 其余的为均质性, 内部洁净; 不同颜色的立方氧化锆的吸收光谱、紫外荧光以及滤色镜下的变色情况均存在差异; 浅紫色立方氧化锆的吸收光谱特征表明它是Nd致色. 能谱分析结果表明: 彩色立方氧化锆的常见元素有Zr, Y, P, Hf, Ca等; Er, Ce, Fe分别是粉红色、红色、酒黄色立方氧化锆的致色元素; 当Y2O3的摩尔分数大于或近于7%时, 立方氧化锆为立方面心结构且内部洁净; 当Y2O3的摩尔分数小于5%时, 立方氧化锆表现为非均质性且内含大量定向分布的白色脱溶物. 用拉尔森改写的格拉斯顿-代尔公式计算其近似折射率为2.12～2.19.

Study on Gemmological Character of Synthetic Colourful Cubic Zirconia

Purple, light purple, light yellow, pink, deep yellow, brown and red cubic zirconias have sub adamantine luster and their fire is obvious. Their density and relative hardness are 5 99~6 34 g/cm 3 and 8~9, respectively. Pink cubic zirconia is anisotropic and a lot of white material distributes orientedly in it. The others are isotropic without any inclusions by magnified 40 times. Cubic zirconias with different colours have different absorption spectra and ultraviolet fluorescences and colours under filter. Absorption spectrum of light purple cubic zirconia indicates that Nd is its colouring element. The XRF analysis indicates that Zr, Y, P, Hf and Ca, etc, are common in colourful cubic zirconia and Er, Ce, Fe are colouring elements of pink, red, deep yellow cubic zirconias respectively. Cubic zirconia is isotropic when mol fraction of Y 2O 3 is more than 7% or nearly 7%, but cubic zirconia is anisotropic and there is a lot of white material oriented in it when mol fraction of Y 2O 3 is less than 5%. According to Glasden dell formula modified by Larsen, approximate refractive index is 2.12~2.19.