When doing your research on diamonds you will most certainly have stumbled upon the term “light performance”. In this context you might also have heard of Idealscope and ASET images. The light performance of a diamond actually describes how the diamond performs in light: Whether it reflects a lot of light back to the viewer or whether a lot of light just leaks through the diamond. This the deciding factor in the brilliance, fire and scintillation of a diamond. And in fact it is what the beauty of a diamond hinges upon.
The concrete way the light gets reflected is dependent on the diamond cut and this is also why this is the most important factor in the beauty of a diamond!
Now, just looking at the diamond proportions and symmetry of a diamond is not enough to make an in-depth analysis on the light performance of a diamond. Especially if you are comparing different diamonds to each other.
This is due to the fact that the light performance of a diamond hinges much more upon the diamond cut than the diamond symmetry. For many people this is hard to understand at first!
However, just imagine a diamond that is perfectly symmetrical but that has a too steep or too shallow pavilion angle:
It is easy to see why such a diamond will not have an excellent light performance. However, in two diamonds with the best diamond cut a diamond with better symmetry will perform better.
Idealscope and ASET images can help you evaluate the light performance of a diamond. Hearts images viewed through a hearts-and-arrows viewer on the other hand will help you evaluate the symmetry of a diamond. They are often provided for hearts and arrows diamonds which are diamonds well known for being super symmetrical.
In this article I will introduce the Idealscope, ASET scope and the hearts and arrows viewer to you. On the following pages we will then learn in detail how to evaluate and analyse those images.
By the way, if you really want to make an educated decision you should at least have a look at the Idealscope image of a diamond before buying it. James Allen, Brian Gavin and Whiteflash are the only diamond vendors that will readily provide these information.
Differences between the Idealscope and ASET Scope
The Idealscope is an invention by Gary Holloway who is a well-known authority in the diamond industry. He is also the inventor of the Holloway Cut Advisor which is a very useful tool in weeding out low-performing diamonds based on their proportions. Read my article on the drawbacks of the Holloway Cut Advisor to get to know more.
The Idealscope is a hand-held version of the Firescope that was invented in the 1980es by Mr. Kazumi Okuda in Japan.
The ASET Scope on the other hand was invented in 2005 by AGS (American Gem Society) which is among the two most reputable grading labs in the world. AGS even uses ASET results to determine the cut grade of a diamond.
Nowadays, both Idealscope and ASET images are extensively used to evaluate the light performance of a diamond and in fact online vendors like James Allen, Brian Gavin and Whiteflash readily provide these information. Check them out!
The main difference between an Idealscope image and an ASET image is the fact that the ASET Scope uses several colors to represent areas of light leakage and of light entrance. For beginners ASET images might therefore be easier to interpret.
On the picture below you can see an ASET Scope, an Idealscope and what kind of results you can expect of both:
By the way, the portable versions are very popular because you can always take them along. The only issue you might have with the portable version is that the light source can be different depending on where you use it. This is why professionals always use an independent light source when using the Idealscope or ASET Scope:
For most consumers however, it will not be so much of an issue of how to make your own Idealscope or ASET image. Every good brick and mortar and online diamond store should be able to provide these images when asked.
In the tutorials on the next pages we will go through an in-depth course of evaluating Idealscope and ASET images. For right now, I just want you to understand that both Idealscope images and ASET Scope images are both perfectly suitable for doing the job. If you only have one, that’s okay but if you can have both you will be sure to make the most educated decision.
Whereas for round cut diamonds I don’t have any preference, I would prefer to have ASET images for fancy shaped diamonds. This is simply due to the fact that fancy colored diamonds typically reflect much less light than round cut diamonds. Therefore more concise information are required for fancy shaped diamonds:
Hearts images viewed through a hearts and arrows Viewer
Now, you should not mix up Idealscope or ASET images with hearts images. Hearts images come into being when you make a picture of a diamond through a hearts and arrows viewer.
For hearts and arrows viewers there are also hand-held devices and desktop devices that work together with the computer. Corporations and grading labs will rather use desktop solutions that are high-tech and can simultaneously calculate proportions. However, a hand-held hearts and arrows viewer will be more than enough to give you lots of information about the symmetry of a diamond.
A hearts and arrows viewer can depict hearts and arrows in a diamond but only in a diamond that actually is a hearts and arrows diamond. Only around 1% of all round cut diamonds worldwide are actually real hearts and arrows diamonds. In my article about hearts and arrows diamonds I have taken a look at the question whether hearts and arrows diamonds are actually worth buying.
Whether you see hearts or arrows will depend on how you put the diamond into the hearts and arrows viewer. If you put it table-down you will see hearts and if you put it table-up you will see arrows:
By the way, sometimes you can see blue, red, orange and green hearts images. The most popular color though is red because it can provide the stongest contrasts:
In my later tutorial I will show you exactly how to evaluate a hearts and arrows image and how to differentiate between true H&A diamonds and near H&A diamonds.
Now, it is entirely sufficient to only look at the hearts image of a diamond to determine whether it is a true hearts and arrows diamond. If the hearts are perfect the arrows will be perfect, too. That is why diamond experts usually only look at the hearts images to evaluate the symmetry of a diamond.
Thus, you need not worry so much about the arrows image.
Let us practice evaluating Idealscope images, ASET images and hearts Images
The way you should go about choosing your diamond is to narrow down your search to the best three options that you could find! All these options should be within the perfect diamond proportions for round cut diamonds.
Then, in order to make the best decision you should look at the Idealscope and ASET images of each diamond. For diamonds advertised as hearts and arrows diamonds it is also vital to check the hearts image to make out which diamond has the better symmetry.
Making these kind of decisions can be tough sometimes and so you will have to know exactly what to pay attention to in every image.
Let us begin with the Idealscope image evaluation on the next page.