浅论欧泊的加工

A Tentative Discussion on the Manufacturing Characteristics and Skills of Opal

欧泊具有特殊的变彩效应,是一种含水宝石和含有脉石的宝石,具有独特的加工性质,如硬度低、脆性强、怕热、色彩丰富、透明度多样、折射率极低、具有星光和猫眼特殊光学效应等。本文从欧泊的加工性质和品种分类出发,阐述了琢型设计和定向设计,着重探讨了欧泊的加工技巧,即在检查—定位—分割—预型—打磨—抛光加工全过程中自始至终处于冷加工状态,磨机、夹具和磨料之间的协同关系以及各种加工注意事项。最后从定向、琢型、比例、平衡性和抛光修饰度等几个方面探讨了欧泊的切工质量评价标准。

Precious opals have a unique play-of-color effect and are composed of hydrous gems and gangue-bearing gems, which have particular fashioning properties such as low hardness, strong brittleness, sensitivity to heat, abundant hues, various transparences, low refractive index, and optical effects of cat＇s-eye and star. On the basis of stud- ying systematic fashioning properties and species classification of opals, this paper describes the designing of cuts with special emphasis on the cooling fashioning from the beginning to the end, tongs, abrasive powders and the correlations of gem opals and various notes in the whole cutting process of inspecting and orientating, dividing （sawing）, performing （shaping）, cutting （faceting）, and polishing. On such a basis, this paper puts forward the appraising standards for the quality of the cut of gem opals from the aspects of orientation, shape of cut, proportions, balance and polishing.