不同产地翡翠的紫外-可见吸收光谱特征研究

翡翠为一种珍贵的玉石。不同产地的翡翠价值差异较大，有些不法商人以某些产地的翡翠冒充缅甸翡翠以获取高价。迫切需要一种可靠方法来确定宝石地理起源，翡翠的产地研究具有重要的宝石学意义，目前主要在翡翠生成时代、矿物组合、硬玉组分含量等方面探讨不同产地翡翠，缺乏快速有效鉴别产地的方法，以缅甸、俄罗斯、危地马拉翡翠为研究对象，对不同产地相同厚度翡翠样品的谱学研究发现：不同产地翡翠紫外-可见吸收光谱中都存在两个明显的吸收峰，紫区437 nm的吸收峰为Fe3+的吸收，430 nm处的吸收峰为Ｍn２＋的自旋禁阻跃迁所致，但是三个产地翡翠紫外-可见吸收光谱的吸收系数范围不同，430 nm处吸收系数峰值范围小于0.62，437 nm处吸收系数峰值小于0.66时，为缅甸翡翠，430 nm处吸收系数峰值范围大于1.1，437 nm处吸收系数峰值大于1.1，为危地马拉翡翠，430 nm处吸收系数峰值范围0.62~1.14，437 nm处吸收系数峰值范围0.66~1.1时，俄罗斯、危地马拉及缅甸翡翠紫外吸收波段重合，为三个产地翡翠共同区域。采用激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)确定MnO和FeO元素含量，发现不同翡翠产地紫外-可见430和437 nm吸收峰值与MnO和FeO元素含量呈正相关关系，该研究为紫外-可见吸收光谱技术应用于翡翠产地快速鉴别，有一定的实用性和可行性。

Study on UV-Vis Absorption Spectra of Jadeite From Different Origins

Jadeite is a kind of precious jade. The value of jadeite from different producing areas varies greatly, and jadeite from other origins passes off as Myanmar Jadeite to obtain a price increase. There is an urgent need for a reliable method to determine the geographical origin of jadeite. The research on the origin of jadeite has important gemmological significance. At present, jadeite from different origins is mainly discussed in the aspects of the generation age, mineral assemblage, jadeite component content, etc. There is no rapid and effective method to identify the origin. This paper takes jadeite from Myanmar, Russia and Guatemala as the research objects. It is found that there are two obvious absorption regions in the UV-Vis absorption spectrum of jadeite from different areas. The absorption peak at 437 nm in the ultraviolet region is the absorption of Fe3+, and the absorption peak at 430 nm is caused by the spin forbidden transition of Mn2+, but the absorption coefficient ranges of the UV-Vis absorption spectra of jadeite from the three origins are different. The absorption coefficient peak range at 430 nm is less than 0.62, and the absorption coefficient peak at 437 nm is less than 0.66, which is Myanmar Jadeite, and the absorption coefficient peak range at 430 nm is greater than 1.1, When the peak absorption coefficient at 437 nm is greater than 1.1, it is Guatemala jadeite. When the peak absorption coefficient at 430 nm is 0.62~1.14, when the peak absorption coefficient at 437 nm is 0.66~1.1, the jadeite areas of Russia, Guatemala and Myanmar coincide, which is the common area of jadeite from three origins. The MnO and FeO elements’ content was determined by laser denudation inductively coupled plasma mass spectrometry (LA-ICP-MS). It was found that the peaks of UV-Vis absorption coefficients at 430 and 437 nm in different jadeite origins were positively correlated with the content of MnO and FeO elements. This study UV-Vis absorption spectroscopy technology to the rapid identification of jadeite origins, which has certain practicability and feasibility.