Of all the metrics considered in a total cut grade, I personally favor this subject most.
Why? Scintillation embodies all the characteristics we have discussed so far; contrast, brightness, fire & leakage and incorporates, into motion, a term which I can simply refer to as "the dance".
Each cut has a unique dance all its own and that dance takes a new step once the diamond is brought into different viewing environments. Whether you are comparing two new ideal cut rounds or even 2 new ideal princess cuts. Each has it's own "dance" that is unique to its own facet structure and optical signature. There is no best when it comes to scintillation which is why, in this gemologists opinion, is a factor that can not be labeled as "best" (neither can their ultimately be with regards to brightness and dispersion since these boil down to personal preference as well). I have been listening for years from factories who deem their product as "the most brilliant" and each of these factories do indeed cut a lovely product. "Best" however is left up to the person who is voting with their hard earned dollars because best to one person is not necessarily best to another.
Scintillation, in layman's terms is most commonly referred to as "the sparkle factor". Measuring or determining scintillation is not an easy task as you have now learned and seen diamonds in varying lighting environments and how they change in appearance. You have been observing scintillation in every moving graphic we have provided in this tutorial so far as scintillation is simply defined by GIA as...
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Sparkle: The appearance, or extent, of spots of light seen in a polished diamond when it is viewed face-up that flash as the diamond, observer, or light source moves.
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Pattern: The relative size, arrangement, and contrast of bright and dark areas that result from the internal and external reflections seen in a polished diamond when it is viewed face-up while that diamond is still or moving.
The first definition under sparkle primarily covers your strong ambient and direct light sources and always involves movement. The addendum to that definition under pattern primarily covers your hemisphere lighting and includes a static (still) view. "Patterning" within the diamond now becomes an issue to be considered in what would properly be termed "static scintillation". We will be exploring patterned diamonds and their impact upon scintillation in this chapter and would be a good place to start.
If one were to request, "I want a very scintillating diamond", a pro could respond by saying ... "this is a very scintillating diamond" or "that is a very scintillating diamond" however a few questions are raised.
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