The Holloway Cut Advisor is a great tool to weed out low performing round cut diamonds. However, you need to be aware of the Holloway cut advisor cons so that you don’t solely rely on the results of the Holloway Cut Advisor. This way you can use the Holloway Cut Advisor in the way it was meant to be used.
I will tell you how to use the Holloway Cut Advisor correctly and what kind of drawbacks there are.
How to use the Holloway cut advisor?
The Holloway Cut Advisor is a free online tool that was developed by Gary Holloway and that you can find here.
It is very simple and easy to use: You simply type in the crucial proportions of your diamond into the Holloway Cut Advisor. You can find these proportions on your GIA or AGS grading report.
Then you click on “Go” and the HCA tool will give you a result that might look something like this:
For one thing the HCA tool will give you a score of your diamond. In our case the score is 1.3 points. Any diamond with a score below 2 will most likely not be a poor performing stone in terms of its light performance! Such a stone is worth considering. Any diamond with a score of more than 2.0 should be discarded.
Furthermore the result indicates whether the diamond would receive the best cut grade by both GIA and AGS. There is an x mark on the graphic which indicates the diamond’s position in terms of light performance. If the x mark is within the white outline it will receive the best cut grade by AGS and if it is within the green outline it will receive the best cut grade by GIA. In our case the x mark is both within the white and the green outline so that the diamond would receive the best cut grade by AGS and GIA.
What are the Holloway Cut Advisor cons?
So, is the Holloway Cut Advisor a great tool to choose the best diamond?
No! The HCA tool is not a selection tool but a tool for weeding out diamonds with a bad light performance. My advice and also the advice of the creator of the HCT tool is to use the HCA tool only as a rejection tool for all diamonds with a score greater than 2.
All in all you have to be aware of the following drawbacks of the Holloway Cut Advisor:
The Holloway Cut Advisor does not take all facets into consideration that have an impact on the light performance of a diamond. The HCA tool disregards any minor facets (such as the star facets and the lower and upper girdle facets) when making its calculation. In reality though, the length of the lower girdle facets impacts the sparkling style of a diamond. A lower girdle facet with a bigger height would result in the diamond exhibiting pin flashes of light. A lower girdle facet with a smaller height however would result in a diamond with broader flashes of light. The Holloway Cut Advisor does not tell you anything about it.
The HCA tool also does not take symmetry and polish into consideration at all. That is why even if a diamond should be below the 2.0 score, you will still have to make sure that the symmetry and polish are okay.
Furthermore, the Holloway Cut Advisor does not tell you anything about the color and clarity of a diamond. But so much should be obvious. You will have to make sure by yourself that the diamond you choose will be eye-clean.
Of course this is particularly important for buying diamonds within the VS1 – SI2 clarity range to get the best bang for your buck. For instance the SI1 diamond on the left is not eye clean while the SI1 diamond on the right is eye clean:
Moreover, even diamonds that have an Excellent cut grade and an Excellent symmetry grade can look pretty different. GIA for instance allows for a lot of variance inside their best cut and symmetry grades. Just have a look at the two diamonds below. Both have an excellent cut grade and an excellent symmetry grade by GIA:
The Holloway Cut Advisor score itself would not always be able to take this into consideration. And this is where the Holloway Cut Advisor comes to its limits. In the end you should never buy a diamond blindly and always have a close look at it before buying it. Even if you use the Holloway Cut Advisor.
By the way, the best place to pick eye-clean diamonds even among the lower clarity grades is James Allen as it provides 360° high definition videos of all its diamonds.
Once you have singled out low performing diamonds you will have to select the best diamond by looking at an Idealscope image of each diamond. Idealscope images will give you very precise data on the light performance of a diamond and quickly reveal to you how much light leakage there is in a diamond.
That being said I think that the Holloway Cut Advisor is a great tool to narrow down your diamonds to the ones with a decent light performance. One just has to be aware that the Holloway Cut Advisor is exactly that and nothing more!