Blue Opal From Peru
-
摘要: 秘鲁蓝欧泊是近年来新出现的宝石品种。通过对该类蓝欧泊的宝石学特征进行综合研究,初步证实,秘鲁蓝欧泊的矿物成分主要为蛋白石并含有不等量的α-方英石及α-鳞石英。在高温下(1 100℃),蓝欧泊中的蛋白石、α-方英石和α-鳞石英热相变为β-鳞石英。揭示蓝欧泊中的水主要以吸附水、结构水的形式存在,其内所含的Cu2+杂质离子趋向与H2O分子结合成[Cu2+(H2O)4]2+水合离子,在八面体晶体场中,产生761 nm的2Eg→2T1g自旋允许跃迁吸收带,指出[Cu2+(H2O)4]2+水合离子是导致蓝欧泊呈色的主要缘由Abstract: Blue opal from Peru is a new variety of gemstone. The comprehensive research on the gemmological features of this kind of blue opal shows that it is composed mainly of opal and minorly of α christobalite and α tridymite. At high temperature (1100℃), the opal, α christobalite and α tridymite in the blue opal are thermally transformed into β tridymite. The water in the blue opal occurs mainly in the form of planar water and structural water, with its Cu2+ impure ions tend to combine with H2O molecules into [Cu2+(H2O)4]2+ hydrated ions. The presence of 761nm 2Eg→ 2T1g spin permitted transition absorption band in the octagonal crystal field indicates that the colouring of the blue opal is attributed mainly to [Cu2+ (H2O)4]2+ hydrated ions.
-
Keywords:
- blue opal /
- colouration mechanism /
- thermal transformation /
- Peru
-
-
[1] Jaroslav H K, CzechR.Gem stones ofPeru[J].The Journal of Gemmology, 2001, 27 (6):328-334
[2] Koivula J I, Kammerling R C.F ine greenish blue opal[J].Gems and Gemology, 1991, 27 (2):120-121
[3] 法默V C.矿物的红外光谱[M].应育浦, 汪寿松, 李春庚, 等译.北京:科学出版社, 1982.289-303 [4] 罗谷风.石英族矿物的某些结晶学性质与成因特征[M].北京:地质出版社, 1983.85-105
计量
- 文章访问数: 26
- HTML全文浏览量: 2
- PDF下载量: 1
下载:
