看到篇有关火彩的文章，跟大家分享

这篇文章是威斯康辛大学地质课本里的节选，原文是这样的，我大概翻下重点：
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One may understand brilliance and sparkle in a diamond. But what about fire? What does it mean? It there a fire inside the diamond or is the stone on fire? Of course not.
大家可能懂得钻石的明亮和闪烁，但火彩是什么，不是太明白。

The term fire if often used to describe a diamond. Fire is when light that enters a diamond is split into all the different colors of the rainbow. Think about your car when you’re washing it. When the rays of the sun hut the stream of water, you see a rainbow of colors right? Those bright flashes of color are what we refer to as "fire" in a diamond. You will notice a diamond’s fire in places where the light is lower, such as restaurants or clubs.
火彩是指白光通过钻石之后分出来的各种颜色。在暗处这个火彩比较明显。

（上面蓝色箭头就是火彩路径，看来火彩不在中心而是在边上一圈。）

The amount of fire in a diamond is caused by the proper cuts and proportions of a diamond. With the right cut, fire can be maximized to their full extent. This gives the diamond more sparkle and dazzle! Now, older cut diamonds look like as if they have more fire because they were cut with steep crown angles and flatter tables of the facets.
火彩量由切割决定，旧式大台面，边上角度比较陡中间台面比较大，最出火彩。

If you want to asses a diamond, you also have to consider the other characteristics such as brilliance and scintillation. Brilliance is the white light that emits from the surface and interior of a diamond. It requires both brightness and contrasts in the diamond and refers to how light is reflected back to the viewer, or return-of-light in the diamond trade. When you see a woman who just received her engagement ring and see how it sparkles, that’s the brilliance showing. It is the most important quality to jewelers.
衡量一个钻石，还得考虑明亮度和闪烁度。明亮度是讲的钻石出来的白光（图里面红色路径），由反光量和明暗对比两项决定。

Meanwhile, scintillation is the sparkle effects that a diamond gives off. When you move a diamond around, the flashes and sparkles you see are called scintillation. This is what gives the diamond beauty and life. Brilliance and scintillation are similar, while fire is a different element.
闪烁度是指钻石动起来的时候的明暗面的转变，这个让钻石有生气。明亮度和闪烁度密切相关，火彩跟这俩没啥关系。

How the diamond is cut will determine how much fire or brilliance it has. Most of the time, you can’t have them the best of them all. You may have to make a trade-off for one quality or another. You may have to ask, which you should choose. For the most part, most diamonds are cut more for brilliance and scintillation rather than for fire. When choosing the right diamond, remember that it’s in investment. But it still all depends on what you would prefer. Whether you choose brilliance or fire, matters most is you love it.
明亮和火彩都由切割决定，但这俩不能同时达到最好，切割的时候只能折衷。多数人选择明亮而不是火彩，但你喜欢什么才最重要。