Which Ideal Cut Diamond should you buy?

Ideal Cut Diamond Tips & Tricks:

I’m working with a guy right now via my free Diamond Concierge Service. He  just sent me a link to James Allen, which presented me with 75 ideal cut diamonds within the range of characteristics that he is considering. His question to me was simple. “Which ideal cut diamond should I buy?” I looked over the images for the 75 ideal cut diamonds presented, and figured out which ones were most likely to meet my selection criteria. It’s a little game that I like to play, since I’ve specialized in ideal cut diamonds for the past 30 years. But then I right clicked on each image to open up the diamond details page in a new window. And then I clicked to open each diamond grading report, so that I could look over the details. Because I know that is the only way to teach you what I want you to learn about how to select the best ideal cut diamond.

Ideal Cut Diamond Reviews, James Allen, GIA Excellent 1219018347, SKU 766647Just out of curiosity. Which of the ideal cut diamonds did you select from the four diamonds pictured above? You’re got a good eye, and a good sense of balance if you happened to choose the diamond on the left. It is a 1.01 carat, G-color, VS-1 clarity, GIA Excellent round cut diamond from James Allen. The diamond has a total depth of 61.3% and a 58% table diameter. The pavilion angle of 40.8 degrees is going to produce a high volume of light return. While the 35.0 degree crown angle produces a virtual balance of brilliance (white sparkle) and dispersion (colored sparkle / fire). The 75% lower girdle facet length should produce broad spectrum sparkle, which is larger in size. The diamond has a medium to slightly thick, faceted girdle, and no culet.


These proportions are within the preferred range outlined in the article 15 Seconds to Diamond Buying Success. And as you can see by the clarity photograph, the diamond exhibits really nice contrast brilliance. It would be nice to have reflector scope images by which to judge the degree of optical precision. However James Allen does not routinely provide ASET Scope and Ideal Scope images for the majority of ideal cut diamonds in their inventory at this time.

The other three diamonds do not meet my selection criteria. There is no point in discussing why, they simply don’t have what it takes by my standards. Understand that my intent is to help you select the best ideal cut diamond available. I’m not simply trying to get you to buy a diamond using one of my affiliate links. So we’re going to open up 75 diamond details pages, and figure out which of these ideal cut diamonds from James Allen is the very best.

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Ideal Cut Diamond Proportions:

Since I’m waiting for 75 diamond details pages to open in separate tabs within my internet browser, this seems like a good time to talk about proportions. Here’s what you’re going to look for:

  • Total depth between 59 – 61.8%
  • Table Diameter between 53 – 58%
  • Crown angle between 34.3 – 35.0 degrees
  • Pavilion angle between 40.6 – 40.9 degrees
  • Thin to Medium or Slightly Thick, faceted girdle
  • Culet size of GIA none or AGS pointed (same thing)

Ideal Cut Diamond reviews James Allen, SKU 779314Note that I really prefer that the crown angle be between 34.3 – 34.9 degrees, but we have to accept 35.0 degrees because of the way the GIA rounds off their measurements. I don’t necessarily open every diamond grading report. First I look at the Diamond Specifications provided on the diamond details page, and eliminate any options that do not feature a crown and pavilion angle within the range recommended above. Clearly the 32.0 degree crown angle and 41.0 degree pavilion angle featured on this 1.07 carat, G-color, VS-2 clarity, GIA Excellent cut round diamond from James Allen don’t cut it. It should also be noted that the pavilion depth of 43.5% happens to be the critical tipping point where light begins not to strike fully off of the pavilion facets. This will cause a decrease in the volume of light return. This is not a diamond that I recommend buying.


In the end, I ended up clicking on the GIA diamond grading report icon to open up 28 diamond grading reports. Either because the combination of crown and pavilion angle met my selection criteria, or because that information was not provided within the Diamond Specifications on the diamond details page. Seven of the GIA Excellent cut diamonds met my selection criteria by the numbers. All of these ideal cut diamonds are great options:

James Allen ideal cut diamond, SKU 559063, AGSL 104078405001The only option that featured a reflector scope image is the 1.06 carat, F-color, VS-2 clarity, James Allen True Hearts diamond. This diamond is actually graded by the American Gem Society Laboratory (AGSL) with an overall cut grade of AGS Ideal Cut. However the diamond grading report does not feature the Angular Spectrum Evaluation Technology (ASET) scan which is standard on the more advanced AGS Light Performance Diamond Quality Documents. The diamond shows only minor variances in the size and shape of the hearts. If you look closely, you’ll be able to see a little extra space around the tip of the hearts in the 5-7-8-10 o’clock positions. The heart in the ten o’clock region is a little smaller than the others. This diamond does not meet my criteria for Hearts & Arrows, but it’s a better than average ideal cut diamond. The diamond looks great in the Ideal Scope image too!


Search Brian Gavin Signature Round DiamondsWe set the standard for Hearts and Arrows Diamonds...

The Super Ideal Cut Diamond Classification:

I could have made my life easier, by simply limiting the search to the super ideal cut diamond inventory of Brian Gavin. The fact of the matter is that all of the ideal cut diamonds produced by Brian Gavin, have proportions that meet my selection criteria. Brian Gavin produces what I refer to as super ideal cut diamonds. Those are ideal cut diamonds which are cut to proportions that represent “the sweet spot” or center range proportions designated for the zero ideal cut rating; and which exhibit a crisp and complete pattern of hearts and arrows.

I’ve actually never rejected a Brian Gavin Signature round diamond for diamond cut quality. Plus the diamond details page for every Brian Gavin Signature ideal cut diamond has everything that I need to judge the degree of optical precision:

  • ASET Scope image.
  • Hearts and Arrows Scope image.
  • Ideal Scope image.

Every diamond has an overall cut grade of AGS Ideal-0 as determined on the Light Performance based grading standard. This grading platform uses Angular Spectrum Evaluation Technology (ASET) to demonstrate how bright the diamond is going to be. It also demonstrates how evenly light is being distributed throughout the diamond. The diamond details pages also feature a clarity image of the diamond, and a high resolution video.

Search Brian Gavin Signature Round DiamondsWe set the standard for Hearts and Arrows Diamonds...

I happen to be partial to the production of Brian Gavin super ideal cut diamonds. Brian  used to produce diamonds for the Nice Ice private label. I’ve purchased literally thousands upon thousands of diamonds produced by Brian Gavin. Thus I know exactly what to expect from the brand. Consistency. 100% consistency. No guesswork or finger crossing required.

Naturally the cost of a Brian Gavin Signature Hearts & Arrows diamond is going to be higher than the cost of a standard ideal cut diamond. This is because it takes about four times longer to polish a diamond to this level of perfection. Time costs money. A turbo charged Porsche 911 that has been fine tuned for racing performance, costs more than a standard Porsche 911 that just rolled off the production line. The degree of performance will be different also.

If you want to Win the Light Performance Gran Prix, my advice is for you to buy the Brian Gavin. There is no need for me to provide a list of Brian Gavin Signature round diamonds that I recommend. The fact is that I’ve yet to reject a single diamond produced by Brian Gavin for diamond cut quality. There is the possibility that I might not like an inclusion or two, but we can address that on a stone-by-stone basis. Feel free to take advantage of my free Diamond Concierge Service.

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Where to buy an Ideal Cut Diamond:

Obviously Brian Gavin Signature super ideal cut diamonds are my first choice. I’m also partial to the hearts and arrows production of Crafted by Infinity. CBI is another producer of super ideal cut diamonds, who used to be a primary supplier of diamonds for the Nice Ice private label. Crafted by Infinity diamonds are distributed online via my friend Wink over at High Performance Diamonds.

When I search for an ideal cut diamond on behalf of clients, I tend to conduct my search in this order:

Why do I search for ideal cut diamonds in this particular order of vendors? Because this tends to be the order that I’m most likely to find the degree of perfection that I’m looking for. If Brian Gavin or Crafted by Infinity happens to have a diamond within the range of carat weight, diamond color, diamond clarity, and price that my client is considering, I know that it’s going to be drop dead gorgeous!

I find the quality of hearts and arrows diamonds offered by Victor Canera to be better than the James Allen True Hearts diamonds that I’ve seen, but not quite up to the production standards of Brian Gavin or Crafted by Infinity. So Victor Canera is my third choice when it comes to diamond cut quality… If I haven’t found what I’m looking for by that point, then I check out James Allen, then I venture over to Enchanted Diamonds, and then Ritani.

The last three vendors, Blue Nile, B2C Jewels, and Zoara rarely provide diamond photographs on their diamond details pages. Thus you’re essentially buying with little more than the information provided on the diamond grading report. Although occasionally I’ve been able to find additional images via the multiple listing service that I subscribe to as a trade member. Ask me whether images are available if you are considering a diamond from one of these companies. It only takes me a minute or two to look up a diamond. Rest assured that I’m going to replace whatever link you send me with one of my own affiliate links, in hopes that you’ll use my link if you decide to purchase the diamond.

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