Ideal Cut Diamonds Explained – Proportions to Maximize Light

Ideal Cut Diamonds Explained – Proportions to Maximize Light

Curious about the concept of an impeccable diamond cut or seeking guidance on acquiring one? Look no further!

Within this comprehensive Twirl Weddings guide, I will delve into the intricacies surrounding the procurement of flawlessly cut diamonds and elucidate why they possess considerable value.

Moreover, I will address prevalent inquiries regarding the purchase of an ideal cut diamond, such as:

  • Does an ideal cut diamond equate to an excellent cut diamond?
  • Is it possible for every diamond shape to qualify as an ideal cut diamond?
  • Do super ideal cut diamonds surpass the quality of ideal cut diamonds?

What Defines an Ideal Cut Diamond?

An ideal cut diamond embodies the craftsmanship of skilled artisans who meticulously shape and polish it, ensuring precise proportions and symmetry for optimal light performance. It represents the highest cut grade acknowledged on diamond grading reports and certificates.

The Gemological Institute of America introduced the notion of cut grades, which form part of the four essential factors determining diamond quality, known as the 4Cs. Alongside diamond clarity, color, and carat weight, the diamond cut serves as a fundamental element in evaluating the overall excellence of a loose diamond.

Diamond cut grades are categorized into five distinct classifications: Ideal/Excellent Cut, Very Good, Good, and Poor. Jewelers predominantly offer diamonds with Ideal Cut/Excellent Cut, Very Good, and Good cut qualities.

Buying Ideal Cut Diamonds – (Pros and Cons)

Similar to any acquisition, opting for an ideal cut diamond for your engagement ring entails certain disadvantages. However, should these limitations be significant enough to influence your decision? The verdict lies in your hands.


  • Unparalleled diamond cut excellence for your precious stone
  • Precisely calibrated proportions deliver extraordinary radiance and scintillation
  • Accompanied by a comprehensive diamond grading report


  • Ideal cut diamonds come with a higher price tag
  • Ideal cut diamonds may visually appear smaller in size

Feasibility of Ideal Cut Diamonds Across Various Diamond Shapes

Surprising as it may be, the revelation awaits that solely round-cut diamonds possess the essence of true ideal cut diamonds. The rationale behind this lies in the fact that round diamonds stand alone in their ability to be fashioned with precise proportions and flawless symmetry. All other diamond shapes, alas, fall short of achieving impeccable symmetry.

In the realm of diamond appraisal reports, the concept of a cut grade remains absent when it comes to the more extravagant diamond shapes. The term “fancy shapes” encompasses all diamond forms excluding the venerable round diamond. Instead, these reports present numerical measurements and dimensions of the gemstone, alongside the other vital 3Cs.

However, should a retailer choose to forge their own certificates rather than relying on established gemological institutes or laboratories, the possibility of a cut grade being indicated may emerge. Nevertheless, it is ill-advised to pursue the purchase of ideal cut diamonds accompanied by in-house certifications.

Achieving Optimal Proportions in Exquisite Fancy Diamond Shapes

If the exclusivity of round diamonds as ideal cut diamonds holds true, one might wonder about the existence of ideal cut princess cut and cushion cut diamonds.

An intriguing query indeed. Allow me to elaborate.

Certain merchants might classify their fancy shapes based on the cut grade, although it would be more accurate to regard it as cut quality. Considering that many online diamond retailers provide cut grade filters using sliders, it becomes sensible to extend this practice to encompass all diamond shapes. Fancy diamond shapes labeled as “ideal” possess proportions that are ideal, albeit not precisely exact.

Distinct diamond shapes possess unique ideal proportions tailored to their specific form. However, it is vital to acknowledge that only round brilliant diamonds can be meticulously crafted with flawless proportions by skilled diamond cutters, thereby bestowing them with perfection. Conversely, other diamond shapes are encompassed within a broader range of acceptable proportions.

Enclosed within this chart lies a comprehensive depiction of the ideal proportions corresponding to various fancy diamond shapes. It is crucial to bear in mind that even if one selects a diamond falling within the prescribed ideal proportion range, the grading report will not disclose any explicit cut grade evaluation.

Is Buying an Ideal Cut Diamond a Wise Decision?

When it comes to acquiring the ultimate diamond, the process is largely influenced by subjective factors. While there exists a benchmark for what constitutes a superior diamond in terms of quality, including the highest grades across the 4Cs, it is regrettable that the majority of individuals are unable to afford a diamond that excels in every category.

Thankfully, attaining the pinnacle of diamond grades in all aspects is not an absolute necessity. Should one choose to invest in such diamonds, it undoubtedly results in possessing a remarkably rare and valuable gem. However, for those of us who do not possess boundless wealth, this situation actually works to our advantage.

In light of this, when considering the cut quality of your diamond, it becomes imperative to acquire the utmost cut grade or quality that aligns with your means. If you are in the market for a round cut diamond and possess the financial capacity to purchase an ideal cut diamond or an excellent cut grade, I wholeheartedly endorse such a decision.

It is crucial to note that diamond cut is the sole aspect among the 4Cs where compromising in order to save money should be avoided. It is always possible to adjust the carat weight, color grade, or clarity grade without undermining the overall quality.

The quality of the cut directly impacts the brilliance and radiance exhibited by your diamond. Among the various cut grades, an ideal cut diamond stands out by reflecting the highest amount of white light. It is worth noting that diamonds with Very Good cut proportions can still showcase a captivating sparkle; however, an ideal cut diamond surpasses all by reflecting almost the entirety of the light that enters its core.

Conversely, a poorly cut diamond yields a phenomenon termed as light leakage by seasoned gemologists. In cases where the cut quality falls short, white light entering the diamond fails to reflect back through the crown angle. Instead of emanating outward, the light penetrates the diamond and halts within. This excessive light leakage significantly diminishes the diamond’s sparkle, resulting in a lackluster and subdued luminosity.

Although even a well-cut diamond may exhibit slight light leakage, its brilliance and fire will remain relatively unaffected. It is worth noting that the distinction between an Ideal cut diamond and a Very Good cut diamond cut grade may not be discernible to the average individual, although some may possess the ability to perceive the disparity.

Undoubtedly, I strongly recommend the acquisition of an ideal cut diamond or a fancy shape with ideal proportions. However, I understand that financial constraints may hinder this possibility for everyone. In such circumstances, a Very Good cut grade or quality still ensures a well-cut diamond that is perfectly suited for engagement rings.

Excellent Cut vs Ideal Cut Diamond Grades

Within the realm of grading reports, one may observe a disparity among gemological laboratories, with some assigning an Ideal cut grade while others designate an Excellent Cut grade for diamonds. It is widely accepted within the diamond market and industry that an excellent cut quality aligns with the standards and attributes associated with ideal cut diamonds.

RECOMMENDED: GIA Diamond Certification

The distinction arises from the fact that GIA diamonds do not utilize the Ideal cut grade; instead, they employ the term “GIA Excellent” to classify their diamonds. The concept of ideal cut grading stems from the American Gem Society (AGS), which is widely regarded as the second most esteemed gemological laboratory. It was the AGS that introduced the cut quality known as the AGS 0 Ideal cut diamond.

There exists an ongoing debate regarding the superiority between a GIA excellent diamond and an AGS Ideal cut diamond. However, we firmly believe that the ultimate decision should be guided by personal style and preference, allowing individuals to choose according to their own unique inclinations.

Super Ideal Cut Diamonds vs Ideal Cut Diamonds

It is also possible to acquire super ideal cut diamonds; however, they do come with a considerably higher price tag. These diamonds are meticulously cut to exhibit exceptional light performance, surpassing even the standards set by ideal cut diamonds. Nonetheless, it is worth noting that the majority of individuals would struggle to discern the dissimilarity between super ideal cut and ideal cut diamonds.

RECOMMENDED: What is a Super Ideal Cut Diamond?

A genuine super ideal cut diamond boasts a slightly greater capacity for light reflection compared to an ideal cut diamond, although the disparity remains inconspicuous to the naked eye. When faced with the choice between an ideal cut diamond and a super ideal cut diamond, it is advisable to evaluate ASET photos and Ideal Scope images. These visual aids provide customers with valuable insights into the diamond’s light reflection capabilities.

What is the Price Range for Round Brilliant Cut Diamonds of Ideal Quality?

Due to their exceptional precision and optimal reflection of white light, diamond cuts of ideal and excellent quality command the highest prices in the market. Despite their costliness, it is crucial to allocate resources for this expense.

Among diamond shapes, the round cut garners the highest demand and price. Although many assume its popularity is the sole reason behind its high cost, this is not accurate. On the other hand, the cushion cut, ranked as the third most favored shape, offers a comparatively more affordable option within the diamond industry.

It is important to note that the round brilliant shape stands alone in its ability to boast uniform and precise measurements. The facets of no other diamond shape can generate such an extensive reflection of light.


The elevated pricing of these diamonds can be attributed to another factor – a larger portion of the rough material is discarded during the faceting process of round diamonds. Only approximately 40% of the original diamond rough is preserved, while the remaining percentage is discarded. Conversely, princess cut diamonds retain around 70% of the rough material, making them a more budget-friendly alternative.

RECOMMENDED: Round Diamonds vs. Princess Cut Diamonds

The price associated with an ideal cut diamond is influenced by various elements beyond its cut quality alone. The remaining three Cs, namely carat weight, color, and clarity, along with the polish and symmetry, also play a significant role in determining its cost.

To provide a visual comparison, let’s consider two diamonds from James Allen. On the left side, we have an ideal cut diamond with an excellent cut grade, adhering to the AGS 0 Ideal standard. On the right side, we find a Very Good cut diamond accompanied by a grading certificate from GIA.


Please note that while the ideal cut diamond exemplifies the highest standard of cutting, the Very Good cut diamond meets GIA’s grading criteria but falls slightly below the ideal range.

Buying Round Brilliant Cut Diamonds

When embarking on the quest for your perfect match, whether you opt for the convenience of purchasing your ideal cut diamond through digital channels or prefer the traditional approach of an in-person transaction, it is crucial to bear certain considerations in mind.

Exercise caution before acquiring an ideal cut diamond devoid of a comprehensive evaluation from a trustworthy laboratory. In the case of naturally formed diamonds, we strongly advocate for the acquisition of GIA or AGS certified diamonds. As for lab-grown diamonds, our recommendation extends to GIA, AGS, IGI, and GCAL diamonds.

It is important to acknowledge that a round diamond may appear relatively smaller when compared to diamonds of equivalent carat weight but different shapes. The size of a round diamond’s table holds less significance in relation to other shapes. Rather, a substantial portion of its weight is distributed within the pavilion, which forms the bottom cone-shaped segment of the round stone. Through a combination of a shorter crown height and a deep pavilion, the diamond effectively reflects and refracts light back through the pavilion angle.

In the event that a significant portion of your budget is allocated towards the acquisition of an ideal cut diamond, there exists the potential to economize on the aspect of diamond clarity. The immaculate polish and flawless symmetry characteristic of a round shape possess the ability to conceal any undesirable blemishes that might otherwise manifest in a diamond of inferior cut quality.


When considering the purchase of an ideal cut diamond, be it a genuine AGS 0 Ideal or a GIA Excellent Cut, the investment proves worthwhile if you have set your sights on a round cut engagement ring. For alternative diamond shapes, it is imperative to adhere to the ideal proportions specific to each shape.

It is important to note that ideal cut diamonds come with a higher price tag compared to Very Good cut diamonds. It is incumbent upon you to assess whether the disparity in cost justifies the investment in your particular circumstances.

In my personal opinion, I wholeheartedly endorse the notion that the expense is indeed justified. I adhere to the philosophy of embracing grandeur without compromise, and this principle extends beyond mere carat weight. When investing in a round cut diamond, the sole diamond shape that boasts flawless measurements, it is imperative to secure the highest cut grade available. By doing so, I ensure that my expenditure translates into exceptional luminosity and radiance, allowing me to fully appreciate the value and splendor of my chosen diamond.

From the very inception of my journey into the realm of diamond jewelry, my initial attraction towards this field stemmed solely from my affinity for radiant objects. Throughout my entire existence, I have held an unwavering fascination for all things that gleam and shimmer. Therefore, without a shadow of doubt, I implore you to bestow upon me an abundance of luminosity. I would willingly forgo an emphasis on carat weight or dedicate efforts to seek out a clarity grade that may be considered lower but still visually appealing to the naked eye.

RECOMMENDED: What is an Eye Clean Diamond?

It is possible that you perceive an ideal cut diamond to be beyond your financial reach, and there is absolutely no cause for concern in that regard. A Very Good cut diamond will suit your needs admirably. I strongly advise against purchasing a diamond below the Very Good cut grade, as the brilliance becomes noticeably diminished as you descend lower on the scale. Descending too far may compromise the durability of your diamond.

Nevertheless, before committing to a Very Good cut diamond, I implore you to contemplate an alternative option.

It may come as a surprise, but it is worth noting that lab-grown diamonds are authentic diamonds that can be priced 20-60% lower compared to their mined counterparts of equivalent quality. Opting for a lab-grown ideal cut diamond provides a significantly more budget-friendly alternative to a naturally mined ideal cut diamond. In fact, you might even have the opportunity to acquire a larger lab-grown ideal cut diamond compared to a smaller mined diamond of the same cut grade.

Ultimately, the decision rests in your hands, allowing you to weigh the available options.

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