Most Expensive Diamond Cut: Why Round Brilliance Costs More and How to Maximize Value

Diamonds have captivated people for centuries. They mark milestones, seal promises and, when cut and polished well, dance with fire and light. When you start shopping for an engagement ring or any piece of fine jewellery, you quickly discover that some shapes cost more per carat than others. In particular, there is one cut that consistently commands a premium: the classic round brilliant. This guide explores why round diamonds are often the most expensive diamond cut, how cut grade influences price and beauty, and how you can balance brilliance with budget when choosing a diamond. As jewellers at Exotic Diamonds, we meet customers every day who ask, “Why are round stones so expensive?” and “Should I consider another shape?” The answers lie in physics, craftsmanship and taste; read on for an in‑depth yet friendly explanation.

Understanding Cut vs. Shape

The terms cut and shape are often used interchangeably, but they describe different aspects of a diamond. Shape refers to the outline of the diamond (round, oval, cushion, princess, etc.), while cut refers to how well the diamond’s facets are proportioned, polished and aligned to maximize sparkle. Thinking of a diamond as a miniature mirror ball helps: shape describes the silhouette, whereas cut controls how those tiny mirrors reflect light back to your eye.

The Gemological Institute of America (GIA) evaluates the cut quality of round diamonds on a scale from Excellent to Poor. A professional gemologist examines each stone and assigns grades based on brilliance, symmetry and polish. An Excellent cut reflects almost all incoming light and provides the highest level of fire and brilliance, whereas a Very Good cut still offers exceptional sparkle but allows slightly more light to escape. Good cuts provide reasonable brilliance at a lower price point, Fair cuts offer little sparkle, and Poor cuts appear dull because light leaks out through the sides. For the greatest beauty, experts recommend focusing on diamonds graded Excellent or Ideal for round stones. When showing customers diamonds in our Patna showroom, we often place a Good‑cut next to an Excellent‑cut round; even under normal lighting, the difference in fire is immediately obvious.

Other grading laboratories such as the American Gem Society (AGS) use similar scales. Regardless of the lab, cut quality strongly influences price: a well‑cut diamond reflects more light, appears larger than its carat weight and commands a higher value. This isn’t marketing hype; we have seen two stones of identical carat weight where the higher‑cut grade looks noticeably bigger on the finger because of the way it handles light.

A Brief History of the Ideal Cut

Modern round brilliant diamonds owe their proportions to a mathematical breakthrough. In 1919 the Belgian engineer Marcel Tolkowsky published Diamond Design, a study that calculated the ideal angles and facet proportions needed to maximize a diamond’s brilliance. Tolkowsky’s research laid the groundwork for today’s “ideal cut” diamonds, and his design became the standard for round brilliants that return the greatest amount of light. This history explains why the round brilliant cut is so revered: it represents the culmination of over a century of research and refinement. It also highlights that round brilliance is not just a fashion trend; it’s the result of scientific innovation.

Why Round Brilliants Are Usually the Most Expensive

Several factors make round brilliant diamonds more expensive than other shapes:

1. Yield and Waste During Cutting – Crafting a round diamond requires the cutter to discard a significant portion of the original rough. Studies show that an average round diamond only uses about 40 % of the original stone. Because so much material is lost when shaping the stone into a perfect circle, cutters must start with a larger piece of rough, raising the cost per carat. In contrast, a princess cut can preserve up to 80 % of the rough, making it more efficient and therefore cheaper.
   
   

2. Popularity and Market Demand – Round brilliants make up approximately 70 % of all diamonds sold worldwide. High demand means suppliers pay a premium for rough suitable for cutting rounds. High demand also allows retailers to charge more for round diamonds. Cultural tradition plays a role: when couples imagine an engagement ring, they often picture a sparkling round stone.
   
   

3. Precision and Labor – Achieving the ideal round brilliant proportions is labour‑intensive. Cutters must precisely align 57 or 58 facets to exact angles to maximize light return. This level of craftsmanship requires more time and skill than cutting many fancy shapes. Our team has visited cutting factories in Surat where specialists spend hours calibrating the angles of a single round stone.
   
   

4. Distinct Cut Grade System – Round diamonds are the only shape for which the GIA assigns cut grades on their certificates. Because cut grade is more precisely defined, rounds can achieve certified Excellent or Ideal status, giving consumers confidence in their sparkle and justifying higher. Fancy shapes lack this unified scale, so their cut quality is less standardized.
   
   

5. Long‑Term Value and Popularity – Round brilliants have remained in fashion for decades. Their timeless appeal and durable shape (no sharp corners to chip) make them a safe investment. According to experts, round diamonds are roughly 65 % more expensive than the least costly shapes. That premium isn’t just theoretical; we see it reflected in resale values when clients trade or upgrade their stones.
   
   

These factors combine to make round brilliants the most consistently expensive diamond cut per carat. However, that doesn’t mean other shapes lack value. Many fancy shapes offer comparable beauty at a lower price.

Price Comparison by Diamond Shape

To illustrate how shape impacts cost, the table below lists approximate starting prices for 1‑carat natural diamonds (H color, VS1 clarity). These figures come from Rare Carat’s 2025 price guide:

The data above show that while round brilliants generally command a premium, niche shapes like marquise or pear can be more expensive at certain carat weights because of limited supply or market trends. Price differences also vary across retailers. For example, James Allen’s 2024 price chart shows round natural diamonds priced around $5,690 for one carat, while marquise diamonds of similar quality are about $5,520. That retailer also notes that pear and marquise cuts are often among the least expensive shapes when considering demand and manufacturing costs. In other words, prices fluctuate based on availability, fashion and the specific combination of carat, color and clarity.

Figure 1: Approximate starting prices for 1‑carat natural diamonds (H color, VS1 clarity) by shape. Round diamonds command a premium over most fancy shapes. Data sourced from Rare Carat’s 2025 price guide.

What Makes Other Shapes More Affordable?

If you love sparkle but want to stretch your budget, consider fancy shapes. Here’s why many of them cost less:

• Higher Yield – Fancy shapes like princess, cushion and emerald cuts utilize more of the rough diamond. A princess cut can use up to 80 % of the original stone, meaning less waste and lower cost. Similarly, emerald cuts make efficient use of the rough. This is why the same piece of rough can produce a larger fancy diamond than a round.
  
  

• Lower Demand – While round diamonds dominate sales, fancy shapes appeal to niche markets. Lower demand allows retailers to price them more competitively. Some shapes, like emeralds, cater to vintage tastes; others, like radiant or cushion cuts, attract those who want something different.
  
  

• Unique Appearance – Fancy shapes offer distinctive aesthetics. Cushions have softly rounded corners reminiscent of vintage designs; princess cuts are modern and angular; emerald and asscher cuts feature elegant step facets that emphasize clarity; marquise and pear cuts elongate the finger and appear larger for their carat weight. Choosing a fancy shape can be an expression of personality.
  
  

• Flexible Cut Grades – Many fancy shapes aren’t graded for cut by the GIA; laboratories focus on proportions like depth and table percentages rather than a strict cut scale. Because there isn’t a standardized “Excellent” cut grade for fancy shapes, price premiums associated with ideal cut certification are lower.
  
  

Balancing Budget and Brilliance

When shopping for a diamond, consider both the cut quality and the shape that speaks to you. Here are some tips for maximizing beauty while keeping costs under control:

1. Prioritize Cut Grade – For round diamonds, choose a GIA or AGS certificate with an Excellent or Ideal cut. Light performance matters more than carat weight or color. A smaller diamond with a superior cut can look more brilliant than a larger stone with a mediocre cut. We often advise clients to choose a half‑carat Excellent‑cut over a three‑quarter carat Good‑cut if their budget is tight—it simply looks better.
   
   

2. Consider Fancy Shapes – Fancy shapes like princess, cushion or oval can give you a larger face‑up size for the same budget. According to the International Gem Society, fancy‑cut diamonds can be 10–43 % cheaper than round diamonds. The same budget that buys a 1‑carat round might buy a 1.2‑carat fancy shape. This extra size can make a big impact on the finger.
   
   

3. Watch Proportions and Symmetry – Even without an official cut grade, proportions matter. Avoid stones that are too deep or shallow, and look for symmetry and polish grades of Very Good or better. Ask your jeweller for light performance reports or images. Many of our clients like to view diamonds under an idealscope or hearts‑and‑arrows viewer to gauge light return.
   
   

4. Factor in Setting and Protection – Shapes with pointed ends (pear, marquise, princess) are more prone to chipping. A protective setting, such as a halo or bezel, can reduce risk. Your choice of metal and prongs also plays a role; platinum prongs provide extra security.
   
   

5. Weigh Personal Style – Ultimately, the best diamond cut is one that reflects your style. Round brilliants are timeless and versatile, but fancy shapes offer individuality. Try on different shapes to see how they complement your hand and aesthetic. You may surprise yourself by falling in love with an oval or an emerald cut after seeing it on your finger.
   
   

Famous Examples and Market Trends

While round brilliants are the best‑known shape, market tastes evolve. Celebrity engagements often drive popularity; for example, cushion‑cut stones have gained attention thanks to Meghan Markle and Priyanka Chopra, leading to increased demand for that shape. Marquise and pear shapes are making a comeback, particularly among buyers seeking vintage or elongated designs. Lab‑grown diamonds have also shaken up pricing: lab‑grown rounds can cost $600 for a 1‑carat H‑VS1 stone compared with $2,700 for a natural round. This price difference means you can opt for a bigger or better‑cut lab‑grown stone within the same budget.

Historic round brilliants show the appeal of high‑quality cutting. For example, the 101.73‑carat Winston Legacy diamond, a perfectly symmetrical round brilliant, sold at Christie’s in 2013 for over $26 million (about $254,000 per carat). Such stones demonstrate how exceptional cutting and rarity combine to create record‑setting prices. On the other end of the spectrum, one of the most famous emerald‑cut diamonds—the 88‑carat Graff Emerald—exemplifies how a fancy cut can also command sky‑high values when combined with size and clarity.

Conclusion: Choosing the Right Cut for You

The round brilliant is often the most expensive diamond cut because of high demand, precision cutting and waste during shaping. However, price varies depending on market trends, carat weight and quality grades. Fancy shapes provide opportunities to save money without sacrificing beauty; many are significantly cheaper than rounds and offer unique looks.

At Exotic Diamonds we curate a wide selection of round and fancy‑shaped diamonds, both natural and lab‑grown. Our experts can help you evaluate cut quality, compare prices and design a setting that protects and showcases your chosen stone. Whether you’re drawn to the fire of a round brilliant or the distinctive silhouette of an oval or cushion, we invite you to contact our team for personalised guidance. Together we’ll find the perfect diamond that balances brilliance, budget and your individual style. The most expensive diamond cut may attract headlines, but the perfect diamond is the one that makes your heart sing when you slip it onto your finger.