The Holloway Cut Adviser diamond evaluation tool estimates performance based on the proportions. According to its creator, Garry Holloway, it is a rejection tool and not a selection tool.
In other words, you should use the HCA to eliminate diamonds that are not likely to perform well. However, the Holloway Cut Advisor does not provide enough insight to make an informed decision.
That's because the HCA can only evaluate diamond proportions, which is an essential component of performance. However, it does not account for optical precision, which is the consistency of facet shape, size, and alignment.
Brian Gavin Signature diamonds offer the best of both worlds if you want to cut to the chase. In other words, they have the right proportions for an excellent HCA Score. Plus, the higher degree of optical precision creates a spectacular sparkle factor.
What Is the Holloway Cut Adviser?
The Holloway Cut Adviser is a rejection tool that evaluates diamond proportions and provides performance insight. In addition, the HCA can help you narrow the search criteria for round brilliant cut diamonds.
Using principles of mathematical ray tracing, the HCA indicates the potential for light return, fire, scintillation, and spread. The basis for those estimations is the rounded proportions data from the lab report.
In that case, it's likely to confirm that this Black by Brian Gavin diamond is an excellent choice. However, it's still good to use reflector scope images to ensure performance.
Holloway Cut Advisor Pros, Cons, and Cost:
One advantage to the HCA is that it's user-friendly and easy to use. The only thing you need to do is paste the AGS or GIA lab report number into the data field and hit enter.
Alternatively, you can enter the proportions information manually into the fields. If the free Holloway Cut Adviser tool were still available, we would advise entering different measurements to see the difference.
Unfortunately, the HCA is now Pay-to-Play, and the cost runs about fifty cents a pop. In contrast, it's free to search using the proportions we recommend in the One Minute Diamond Buying Guide.
Is the Holloway Cut Adviser Accurate?
Many people ask whether the HCA Tool is accurate, and it is to some extent. After all, it is possible to predict performance based on proportions using mathematical ray tracing.
For that reason, the Holloway Cut Adviser is an effective rejection tool. In contrast, it is not a reliable selection method because it cannot account for optical precision.
That is the consistency of facet shape, size, and alignment. Take this 1.08 carat, G-color, VS-2 clarity, James Allen True Hearts diamond, for example.
The diamonds' proportions are within the range we recommend, as indicated in the diamond grading report. You can enter the number from the lab report into the data field to auto-populate the proportions fields.
How to Use the Holloway Cut Advisor:
As shown above, you can auto-populate the proportions fields by entering the AGS or GIA report number. Alternatively, you can manually enter the measurements and then hit enter.
Then, a prompt will appear requesting a subscription key or inviting you to purchase a package to see the results. You will be redirected back to the HCA tool after completing your purchase.
Under those circumstances, we'll repeat that we're going to use this 1.08 carat, G-color, VS-2 clarity, James Allen True Hearts diamond as an example. The diamond grading report number is GIA 2357549956.
As you can see, the proportions are within the range we recommend. In that case, the 40.8 degree pavilion angle should produce a high volume of light return.
Simultaneously, the 35-degree crown angle should also create a virtual balance of brilliance and dispersion. The HCA results for this James Allen True Hearts diamond appear below.
Are HCA Tool Scores Reliable?
Based on the proportions of the James Allen True Hearts diamond, the HCA results are as follows:
As you can see, the HCA indicates that the diamond should have an excellent light return, fire, and scintillation. Consequently, that assessment aligns with my estimation of performance based on the crown/pavilion angle offset.
The HCA is a Diamond Elimination Tool:
James Allen provides Ideal Scope and Hearts' pattern images for True Hearts diamonds. Therefore, we're able to judge the light performance for ourselves.
In this case, the light pink and semi-translucent sections indicate a moderate amount of light leakage. The most likely reason is a lesser degree of optical precision.
In other words, differences in facet shape, size, and alignment create light leakage despite the proportions. Those differences are evident in the image of the hearts' pattern below.
Conversely, the discrepancy between the HCA results and the actual performance is why the Holloway Cut Adviser is a rejection tool. However, under those circumstances, some people will benefit from its use.
Why I Don't Use the Holloway Cut Adviser:
First, I want to clarify that I'm not bagging on the HCA or my friend, Garry Holloway. I think that the Holloway Cut Advisor is an excellent entry-level consumer resource.
However, I'm a professional diamond buyer with 35+ years specializing in the niche of light performance. In that case, I'm not likely to dabble with basic concepts like the HCA.
After all, the Holloway Cut Adviser works in broad-strokes, and I can predict light performance by proportions in my sleep. However, it's also abundantly clear that these hearts are inconsistent in size and shape.
In that case, it's not surprising that this diamond is leaking light despite the proportions. Speaking of which, here are the proportions we recommend for round brilliant cut diamonds.
Best Proportions for Round Diamonds:
It's Not Rocket Science:
Truth be told, it's easier to buy a spectacular-looking diamond online than people make it out to be. You only need to adhere to the proportions specified above or follow the guidelines for other diamond shapes.
Under those circumstances, you set the stage for a high volume of light return and a virtual balance of brilliance and dispersion. Then, you only need to evaluate the clarity characteristics and verify the performance.
Consequently, I can do that in about thirty seconds if the seller provides full details. In other words, that's how long it takes to eliminate a diamond and decide whether it warrants a closer look.
How to Select a Stunning-looking Diamond Online:
It's easy to buy a spectacular-looking diamond online if you have access to the proper insight. However, most diamond dealers do not provide the insight necessary for you to make an informed decision.
Take this 1.04 carat, G-color, VS-2 clarity, GIA Excellent cut round diamond from Blue Nile. The HCA scores it 2.0 Very Good and indicates it may be worth buying if the price is right.
Consequently, the crown angle is beyond the range we recommend. In that case, it's not surprising that the reflector scope images indicate a moderate degree of light leakage.
Generally speaking, Blue Nile does not provide the images necessary to judge light performance. However, I was able to obtain these images from the supplier:
Professional diamond buyers like myself use those reflector scope images to make informed decisions. Please submit an inquiry via our Diamond Concierge Service to see whether reflector scope images are available for virtual diamonds.
Diamond Dealers Who Provide Full Details:
Of course, it's probably faster and easier to use our free Diamond Concierge Service. In that case, you only need to tell us what you're looking for, and we'll do the leg work.
If you're wondering what we get out of it, we may earn a small commission if you use our link to place your order. However, that depends on certain conditions, including whether that click counts as the last referral.
Using the HCA to Choose the Best Diamonds:
The example of a James Allen True Hearts diamond above demonstrates why ASET and Ideal Scope images are essential. In that case, the Holloway Cut Adviser indicates that the diamond has excellent potential.
However, the Ideal Scope image indicates a moderate amount of light leakage. In contrast, the HCA score for this 1.05 carat, H-color, VS-2 clarity, James Allen True Hearts diamond is excellent.
However, the Ideal Scope image verifies that this James Allen True Hearts diamond performs better. In other words, there is less light pink visible under the table facet, so the light return is higher.
Consequently, the ASET map on the AGS Diamond Quality Document for this diamond confirms the light performance. Needless to say that the proportions are within the range we recommend.
Same HCA Score 0.7 Excellent with Better Performance:
This 1.053 carat, G-color, VS-1 clarity, Black by Brian Gavin diamond also gets an HCA Score of 0.7 Excellent. That's not surprising, given that the proportions are in the same spectrum.
Consequently, Brian Gavin holds the patent for maximizing light performance in the modern round brilliant cut diamond. Under those circumstances, they adhere to rigorous production standards.
First, the proportions combination is stricter than anything else I've seen. Second, they polish the minor facets in a way that maximizes the sparkle factor. And yes, it results in a light return difference that is readily apparent.
In other words, the higher degree of optical precision creates more virtual facets within the diamond. Similarly, it also produces more outward-bound sparkle that is more vivid and intense.
Under those circumstances, it is possible to have two diamonds with similar HCA scores look remarkably different due to cut quality. Once again, that is why the Holloway Cut Adviser is a rejection tool and not a selection tool