How to Evaluate Diamonds with an Idealscope?

Learn how to evaluate Idealscope images

If you want to start out examining the light performance of a diamond there is not better place to start out than with an Idealscope image.

It can tell you a lot about where the light is leaking in a diamond and how much light a diamond will actually reflect back to you. Only a diamond that reflects a lot of light back to you will be a diamond full of brilliance, fire and scintillation.

You should always demand an Idealscope image before buying a diamond – no matter whether you are buying in a brick-and-mortar store or online. Some brick and mortar stores have Idealscopes but many don’t. The same applies to online diamond vendors. Most online vendors are only dropshipping their diamonds and thus they are not able to offer you any real Idealscope images.

Check out James Allen, Whiteflash or Brian Gavin if you want to see an Idealscope image before buying a diamond!

How to evaluate an Idealscope image in general?

Understanding how to interpret Idealscope images in general is very easy. Basically there are only three colors you need to pay attention to.

Red and Black:
The red color in an Idealscope image signifies areas of light reflection which are highly desirable. You want your diamond to reflect a lot of light! The dark color symbolizes the symmetrical and distinct dark contrasts in a diamond. You also want to have your diamond to have distinct contrasts because the contrasts will make your diamond appear brighter.

That sounds counter-intuitive but basically it is just the same as with a chess board: It only has half the light return of a completely white board but when you move it, it will appear brighter than the white board. This is due to the scintillation effect caused by the dark contrast.

Chessboard with dark contrasts appears brighter than a completely white area


For this very reason dark contasts in diamond are always welcome. The strongest dark contrasts are provided in hearts and arrows diamonds which offer a very strong contrasting pattern.

Light Red:
The light red color in an Idealscope image symbolizes areas where the diamond is reflecting back less light. Every diamond has some areas of lighter red although in super ideal cut diamonds even these light red areas are harder to make out. The less light red you find in an Idealscope image, the better the diamond’s overall light performance will be.

White / Clear Color:
The white color symbolizes areas of light leakage. It is clear that you want to avoid diamonds with light leakage. Light leakage can occur due to bad proportions. This means that certain angles within the diamond are outside the perfect diamond proportions. Light leakage in such cases might look something like this:

Diamond proportions influence an Idealscope image


Other than that a diamond could also exhibit light leakage due to symmetry issues:


The diamond symmetry also impacts an Idealscope image

(Pictures are courtesy from

Many people think that the diamond cut and the diamond symmetry are exactly the same thing. However, they fail to realize that a diamond could be perfectly symmetrical but for instance have a very steep pavilion angle. This would result in a deep diamond with a terrible light performance:

A steep pavilion angle causes a deep diamond with lots of light leakage

But actually it does not matter so much whether you understand why a diamond leaks light. The most important thing you need to know is that a diamond leaks light. And Idealscope images can help you a lot with that.

I will show you some examples of Idealscope imageges which I want to illuminate the process of choosing the right diamond for you.

How to make an Idealscope image evalutation? Let’s practice!

So, let us practice a little bit and I am sure that you will become pretty good at reading Idealscope images. All examples are used with courtesy of Whiteflash. I have chosen all my examples from their different signature lines so that a comparison like that really makes sense.

The first example below is actually going to be pretty easy:

Whiteflash diamonds Idealscope comparison 1

The diamond on the left is taken from Whiteflash’s A CUT ABOVE signature line which is one of the #1 cuts in the world. The diamond on the right is taken from the Premium Select signature line.

I think that there is no need to circle the areas of white light in the diamond on the right. It is obvious that compared to the left diamond the right diamond is leaking more light. In a case like that it would obviously be the best decision to go with the diamond on the left side.

But let us have a look at a more difficult example that is going to involve 3 diamonds. If you need to you can click on the image to enlargen it:

Whiteflash diamonds Idealscope comparison 2

Haha, what do you say now?

I do be aware that this one is an extremely tough call to make! And indeed, if it were not for one little extra feature that I wanted to show you in this example I think I would have an extremely difficult time choosing the best diamond, too.

Now, in all three diamonds we cannot make out any really white spots that would indicate light leakage. But we can make out areas of lighter red relative to the darker red in a diamond.

So, let us only pay attention to the areas of lighter red. Which diamond has the most areas of lighter red?
I think that it is the diamond on the right.

Alright, then we are only left with the diamond on the left and the diamond in the middle, right? If we were to base our decision only on the spots of lighter red I think it would be a very difficult decision to make. But I would then go for the diamond on the left because to me the diamond on the left seems to have fewer spots of lighter red than the diamond in the middle.

But there is also another reason to go for the diamond on the left side! I will once again compare the left and the center diamond from above to each other:

Areas of light return are preferred to areas of light contrast in an Idealscope image

Look closely at the black contrasting colors! In the diamond on the left the contrasting color solely comes from the arrows in the diamond. As I have told you, the contrasting color is good but if you can have an area of light return instead, it is even better. This is due to the fact that you already have a nice contrast in the arrows anyway.

The diamond on the right however also displays very minute areas of contrast apart from the arrows pattern. I have circled these areas in blue. This is very common and nothing to worry about. However, the contrasting pattern that does not come from the arrows is not that symmetrical. You can clearly see it just looking at the blue circles. They are spread in an uneven manner. In a case like that the brightness-effect through the contrast will be diminished and it is wiser to go for more areas of light return.

Please note, however that these are very tiny differences that you would most likely not notice with your eye. Furthermore, the dark areas that I circled can have a positive impact if they are more evenly distributed. Still, if you are there to make the really best choice this is what you have to do.

The funny thing is that the diamond on the left is from the Expert Selection and not from Whiteflash’s A CUT ABOVE signature line. In this case however, the diamond on the left did not make it into the A CUT ABOVE signature line because it did not have the very best polish grade. In reality though you will most likely never see a difference between the best and second best polish grade. You can read more about that in my post about diamond polish.

I know that such Idealscope analyses can be quite tricky sometimes. So If you have any questions, feel free to leave me a comment or drop me a mail.