A Tentative Discussion on the Manufacturing Characteristics and Skills of Opal
浅论欧泊的加工

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 studying 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.