仿真模拟研究钻石灯下钻石的切工特征与应用

Diamond Cut Characteristic under Diamond Lamp by Simulation and its Application

钻石的切工对评价其价值优劣有着极其重要的作用,人们常借助钻石灯来观察及挑选较好切工的钻石。在不同入射角度的光源下观察钻石,其明亮度相差甚远。为寻找合适的钻石灯光源入射角度,运用仿真软件对冠角27°~38°、亭角39°~43°的标准圆钻型切工钻石的亮光图案在不同入射角度的钻石灯光源下进行仿真模拟,结果显示,钻石灯光源入射角在20°~25°时较易观察及分选出较好切工钻石,此光源入射角范围内较好切工的钻石图案均匀、明亮度较高且具有上半部分图案亮度较高的分辨特征。观察分选钻石时,应把分选板平放在桌子上,钻石台面朝上放置分选板槽中,额头顶住钻石灯灯罩,视线与钻石台面垂直,挑选亮度较高、分布均匀,上半部比下半部明亮的钻石。

Cut ratio plays an important role in evaluation of diamonds. People usually use diamond lamp to observe and choose diamonds which are better cut. However, in different lighting angles, we will observe diamonds with different brightness. In order to find out the most suitable angle to sort diamonds of better cut grade, the authors simulated the brightness of round brilliant diamond （crown angles from 27° to 38° and pavilion angles from 39° to 43°） under illumination source such as diamond lamp in different lighting angles. When the incident angle of diamond lamp is between 20° - 25°, the patterns of better cut areas are uniform and the values of brightness are higher than bad cut areas and the upper half is brighter than the bottom half. The preferable position to observe dia-monds is making diamonds placed in the slots with their table facets up, with the sorting board flat on the table. Rest one^s forehead against the lampshade with line of sight vertical to the table facetsof the diamonds. Use this method to sort diamonds, and the diamonds with higher brightness, uni form brightness distribution mainfest themselves as the upper halves brighter than the bottom halves.