山东蓝宝石的色源和改色研究

STUDY ON THE COLOUR ORIGIN AND DECOLOURATION OF SHANDONG SAPPHIRE

报道了山东蓝宝石的ＸＰＳ，ＳＩＭＳ的测试结果。基于成份分析、光谱测试数据及对改色处理结果的分析，作出了关于山东蓝宝石的色源解释。山东蓝宝石含铁量明显偏高，Ｆｅ^（２＋）－Ｔｉ^（４＋）离子间的电荷转移及Ｆｅ^（２＋）－Ｆｅ^（２＋）离子对的电子跃迁这两种机制的迭加，是造成其色深、失透的基本原因。认为好的改色方法应当是使Ａ，Ｂ，Ｃ三组吸收峰同时降低，并增大蓝光的透过率，以保持其天然的色调纯正不变。

In this paper, colour origin of the natural sapphire of Shandong province, China, was explained, based on XPS, SIMS and absorption spectra, as well as the effects of decolouration treatment in various atmosphers. The iron component in the Shandong sapphire is obviously higher. Darkening of the colour and opacity are resulted from the interaction of the two kinds of mechanisms, i.e. the intervalence charge transfer between Fe￣(2+)and Ti￣(4+) and the electron transition of the exchange-coupled Fe￣(2+)-Fe￣(2+) pair. In order to keep the hue of the sapphire unchanged when decolourated, it is recommended that the three absorption peaks of the sapphire, denoted A, B and C respectively in the absorption spectra, should be lowerd at the same time and the transmittivity of the blue light should be enhanced simultaneously. .