Thursday 22 August 2013

Pricescope Rockytalky Review: Aprilbaby

It’s time for another Pricescope Rockytalky review!

I noticed yet another recent thread that had an interesting question about Whiteflash ACAs. The specific question was whether all ACAs are made exactly the same and would PSers ever recommend against one? The question was raised because of concerns that the ASETs and Idealscope of some ACAs, in particular those under half a carat, varied a bit and that some idealscope also showed what appears to be leakage.

You can read the original thread here.

The short answer would be no they are not all made exactly the same and Whiteflash does not claim that they are. The simple reason being that there are always going to be borderline cases, and you would also expect the rare but unavoidable human error. The general answer is that yes, if you purchase a Whiteflash ACA, it is very highly likely that you will be a satisfied customer. The full answer, however, would require some knowledge of how a diamond is cut, which is going to be the topic of a future tutorial. For now, it is sufficient to know that diamonds cut to super-ideal standards are precision cut, and the cutter is usually able to cut the diamond very precisely. Also, if you’ve read all my tutorials, you will know precisely how each facet affects the appearance of diamond. Equipped with this knowledge, you too would expect there to always be an explanation for what you can see in any image of a diamond whether actual or light performance related.

In the thread, three ACAs in total were brought up for discussion. The first two were compared first:

Diamond 1
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2684406.htm

Diamond 2
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2982215.htm

The first question about these two diamonds was whether Diamond 1 had a better idealscope than Diamond 2. The person who posed the question thought that Diamond 2’s ASET was more dull and the idealscope was more grey and less vibrant. The more experienced PSers handled the question well noting that you should not be comparing the color saturation of different ASET images with each other.

However, no one seemed to look more carefully to see what else could explain the differences seen. Without even looking at the idealscope, you can see that Diamond 1 has more contrast around the edge of the diamond. This is because Diamond 2 has slightly painted girdles. This is of course verified by looking at the idealscope and what I believe is the proper answer to why the idealscope appeared more grey is actually because it has more deep reds in the upper girdles. It is often difficult for untrained eyes to distinguish dark-greys and deep reds in idealscope images. The ASET also tells the same story and you can see it manifesting as ever slightly increased green areas, lengthening in the upper girdles and thickening around the stars facets.

Does the existence of slight painting change what I think about ACAs? Certainly not, because it still exuberates a familiar characteristic contrast pattern under the table facets. You can think of slight painting as a sprinkle or topping to the diamond that you can choose whether to go with or without. Be minded that the reason slight painting is used here is most likely to ensure the diamond is over 1ct in weight.

The next comparison was between Diamond 2 and Diamond 3 below:

Diamond 3
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-2949573.htm

Interestingly, Diamond 3 is a good example of why an ASET tells a clearer story than the idealscope. Untrained eyes are not likely to notice the widening of the leakage areas around the edges indicating steeper upper girdles in an idealscope image. The upper girdles are not so steep that they cause obvious leakage, but under the ASET, it is clear that at least 10 of the 16 upper girdles are steep enough to be returning light from the periphery (green on the ASET). A further inspection of this diamond’s proportions confirms that this is not what I am used to seeing in a typical ACA. Because of this, I had a quick peruse of some of the other ACAs under half a carat and I noticed that there is more variation in proportions in these smaller diamonds than there are for diamonds 1ct and above.

Now I can see how these diamonds still make it to the ACA level, after all, they are still well within my recommended proportions, with precision cut H&A, and near 100% light return. The subtlety here is that where the light return is coming from in the upper girdles is more from the periphery rather than from around a 45 degree angle, the latter in my opinion is preferable. This diamond does not have the best edge to edge light performance and is likely to pick up all sorts of color reflecting from its surroundings.

The conclusion of this review is that most ACAs are made the same, but there are some borderline cases, which I personally would avoid if I were purchasing an ACA. If you are looking for an ACA and have any doubts/questions. Please feel free to send me an email or leave a comment.

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