What are the Holloway Cut Advisor Cons?

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.

Proportions typed into the Holloway Cut Advisor

Then you click on “Go” and the HCA tool will give you a result that might look something like this:

Holloway Cut Advisor results

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:

  • Example of a SI1 diamond that is not eye clean
  • Example of an eye clean SI1 diamond


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:

  • Diamond with Excellent cut grade and Excellent symmetry grade and an appealing appearance
  • Diamond with Excellent cut grade and Excellent symmetry grade but an unappealing appearance

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!

What are the Holloway Cut Advisor Cons?
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Sebastian Naturski loves to write about diamonds and share his knowledge with his readers.
When he is not working on his website he is studying law at Humboldt University of Berlin.
He has taken part in several international law competitions and likes to broaden his horizons.
His other big passion are languages. He is fluent in German, English, Polish and Japanese and got basic skills in French and Spanish as well.


  1. We tried posting another comment – but made a mistake on the diamond specs so reposting.
    Excellent article – very helpful information. We’re currently working with a diamond broker and he’s presented us with a diamond that we believes looks amazing. But after checking the HCA score (4.8) we’re not sure what to think. Can you provide your input on the following diamond:

    Depth 65.6 %
    Table 62 %
    Crown Angle 36.5°
    Crown Height 14.0%
    Pavilion Angle 42.0°
    Pavilion Depth 45.0%
    Girdle Thick to Extremely Thick, Faceted, 7.0%
    Culet None

    • Thanks, Reca! Aside from your diamond’s low HCA score which means poor light performance, the proportions you’ve given suggest it has poor cut as well. I would always recommend opting for an excellent/ideal cut, so maybe you could look into other options. Here are the specs for ideal and super ideal cuts for your reference:

      Standard Round Cut
      Depth – 56.88-63.92
      Table – 52.4-57.5
      Crown Angle – 33.7-35.8
      Pavilion Angle – 40.2-41.25
      Girdle – Thin-Medium

      Super Ideal Cut
      Depth – 61-62.5
      Table – 54-57
      Crown Angle – 34-35
      Pavilion Angle – 40.6-41
      Girdle – Thin-Medium

      Learn more about Diamond Cut in this post.

  2. I am now worried about the diamond we are considering solely because the HCA score is 4.6 (and proportions seem high). GIA round brilliant 6.16-6.17×3.85mm, 0.9ct, K color, VS1, excellent cut, polish & symmetry w/ faint fluorescence. Table size: 58%, Crown Angle: 35.5, Pavilion Angle 41.2, depth 62.4%, girdle thickness slt. thick @ 4%; lower half length is 80% & star length is 50%. Price is ~$3500.


    • Hi Rachel,

      An HCA score of 4.6 means your diamond has poor light performance, though it doesn’t mean that it also has less fire and scintillation. The table size is a bit over the standard proportions (52.4%-57.5%), and the girdle is thicker than the recommended, but all the other dimensions are acceptable. It’s best to see your diamond in person or super zoom to know if the sparkle is good enough for you. Also, you might want to take a look at diamonds with similar parameters on James Allen. They have less expensive pieces, but that doesn’t take away from their superb quality.

  3. Hi,
    I am curious how you feel about this diamond? It is an ideal cut, not super ideal. It has an HCA score of four, which is considered garbage or throw away. However a lot of the specifications are quite adequate. Would your opinion be that this diamond will have a beautiful light performance but would not be as fiery and brilliant as something with an HCA score less than two? Is this diamond even worth the price? For similar carat weight color and clarity with a super ideal cut the price almost doubles…


    • Hi Gina,

      The low HCA score is most likely due to the fact that it has both a steep pavilion and crown angle. For better scores, a steeper angle would have to be counterbalanced by a shallower angle. Thus, this diamond leans more into the fiery ideal cut while definitely losing some brilliance compared to a super ideal cut diamond.

      It’s still good, it’s eye clean, and cheaper compared to diamonds with similar specs, but there might be visible differences when directly compared to a diamond that is within super ideal cut proportions. 🙂

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