Today’s request is from Kim who is considering a 1.75ct FVS2 diamond from Enchanted Diamonds.

Here’s the link to Diamond 1.

Kim is interested in a full review of the stone but specifically mentioned concerns about the inclusions and whether the diamond will be eye-clean. The light performance images also seems to be computer-generated so Kim was not confident in interpreting them. Kim also found another 1.7ct GVS1 diamond that looks like it has better crown and pavilion angles and wants to know if going down to a G-color in this case is better.

Here’s the link to Diamond 2

Let’s take a closer look at these two options.

Diamond 1

Well first of all the good thing is that this diamond is likely eye-clean. The clouds although dark in color is very small and not distracting even when magnified to over 20x. But what about the light performance?

This diamond has a Enchanted Diamonds cut score of 100 so we know that this means the proportions are going to be within the recommended range. However, as far as I know the Enchanted Diamonds cut score doesn’t take into account of what are the best complex combinations of proportions within the recommended range or how good the optical symmetry of the diamond is.

One common mistake I find readers make is to focus too much on the rounded and averaged numbers on the lab report. If the diamond has poor optical symmetry, it means that when you look at each individual facet, those individual crown and pavilion angles might not be in ideal combinations. What this means is that if light performance and finding those ideal proportions are important to you, then to a degree you must also consider optical symmetry.

This is why you never buy a diamond without at least a face up picture and in most cases you will want to see some kind of light performance image. The different types of light performance images are designed to make it easier to evaluate the diamond and you can think of each image being a piece of the same puzzle.

If you have all the pieces then the picture is going to be very clear, but whether you need a hearts image or an idealscope or an ASET depends on what your expectations are and how good the other pieces of the puzzle are.

In this case we have the face up image and a hearts image of the diamond. The face up image is difficult to evaluate because of the white background so light leakage becomes harder to see. Try to identify the areas of light return in the diamond in order to distinguish the color of white light in the picture versus the background colour. In this case there is quite a bit of background colour showing up in the diamond that suggests the diamond may be leaking light.

Looking at the hearts image, you should be able to see a few smaller hearts (especially at the 7 o’clock position). Smaller hearts indicate a steeper pavilion angle so this is one of the most important defects seen in the hearts image. The other things like the clefs, the distorted Vs, and tip of the hearts that don’t come together at a sharp point are all relatively minor. Since the pavilions are the drivers of light return in a diamond, and the aim here has been clearly to find a diamond with ideal proportions, it would be a waste of all of that effort to choose a stone like this especially because the proportions were a bit borderline to begin with.

Diamond 2

As a reminder, here’s the link to Diamond 2 again.

This is another diamond from Enchanted Diamonds that receives a 100 cut score. The lab report shows a crown angle of 34.5° and a pavilion angle of 40.6°. This is always a promising start because a 34.5° crown angle is ideal and gives you more leeway in how steep the pavilion angles can be on each individual facet. The 40.6° pavilion is also a good thing and this combination would be a great choice if you resigned yourself to buying blind because based on numbers alone, you’re improving your chances of getting a better diamond.

In this case we have the face up image, the hearts image, and the ASET image available to us so we can evaluate this diamond’s light performance fully. If you look at the ASET, it shows us that generally this diamond does have decent light performance. Notice however that there is a small area just on the left of the 12 o’clock arrow shaft that is showing weak light return and correspondingly that arrow is misaligned. This is also an indicator that at least one pavilion facet is too steep.

The good thing is that this ASET image is backlit, so it’s a relatively more conservative type of ASET. Visually this isolated area of weaker light return is not really going to have a significant impact on the overall beauty of the diamond. However, if someone were looking for a diamond with ideal light performance and edge-to-edge light performance, then this diamond doesn’t fit that criteria. The ASET also reveals one steep upper girdle at the 11 o’clock due to one dug out upper girdle so there are two things that prevent this diamond from meeting one that I would be happy to recommend.

Nevertheless, this diamond is a significant improvement over Diamond 1 in all categories of light performance and it achieves this by taking a slight hit to the spread of the stone. The weight ratio of this diamond is 1.074 and this is very high. Compare this to the 1.059 weight ratio of Diamond 1, which is high but just within the range I typically recommend. The higher weight ratio on Diamond 2 is mostly because of the 4% girdle.

Recommendation

One of the things Kim was unsure about was whether it is worth going down from F-color to G-color for the right diamond. If you are unsure about F or G, chances are a G-color or even an H-color diamond will be totally acceptable given that it is well-cut. Definitely if you find yourself in a situation where you have to compromise cut to the point where you cannot find a diamond with ideal light performance, then you should try your best to compromise on the other factors that won’t have as much of an impact on the diamond.

Kim has a 19k budget for an eye-clean 1.7ct+ diamond. This budget should be very healthy to get a really well-cut diamond and still have respectable color/clarity. I found a couple diamonds from Whiteflash that you might be interested in.

Diamond 3: 1.684ct GVS2 hearts and arrows diamond

Unfortunately this one would not be considered a good VS2.

Diamond 4: 1.802ct GSI1 hearts and arrows diamond

This one is actually a much better choice. Although it is an SI1, it is a good SI1 and is eye-clean.

Let me know what you think!