Diamond Carat with Loupe and Gia Certificate | Lisa Robin

diamond guides

About Round and Modified Brilliant Cut Diamond?

Round brilliant diamonds can be modified in shape. Learn more.

About Round and Modified Brilliant Cut Diamonds

Q: What is the difference between brilliant cut, modified brilliant cut, and step cut diamonds?

Brilliant cut diamonds : Standard round brilliant with 58 facets designed for maximum sparkle. Modified brilliant cut diamonds : Retain brilliant-style facets but vary in facet arrangement or shape (e.g., oval, marquise). Step cut diamonds : Rectangular facets arranged in parallel lines for a hall-of-mirrors effect (e.g., emerald, asscher).

Q: Which diamond shape sparkles the most?

The round brilliant cut diamond sparkles the most, especially when graded Triple Excellent (GIA) or Ideal (IGI), due to its precise facet arrangement.

Q: Which shapes appear larger?

Marquise, oval, and pear diamonds often appear larger than round diamonds of the same carat weight because of their elongated outlines and greater surface spread. Diamond size comparison chart.

Round Brilliant Cut Diamonds

The round brilliant cut diamond is the most popular diamond shape, accounting for more than 50% of all diamonds sold. Its enduring appeal lies in its facet arrangement: 58 precisely cut facets that maximize light reflection, resulting in unmatched sparkle and brilliance. With optimal symmetry and proportions, a round brilliant reflects light from the bottom and back through the top, producing its signature fire and scintillation.

Parts Of a Round Diamond Graphic | Lisa Robin

$Diamond Light Refraction Based on Depth of Diamond Graphic | Lisa Robin$

Modified Brilliant Cut Diamonds

What is a Modified Brilliant Cut Diamond?

A modified brilliant cut diamond is a diamond that retains the brilliant-style faceting (featuring triangular or kite-shaped facets) but has a facet arrangement or shape that differs from the traditional round brilliant. These modifications can include changes in the number, orientation, or pattern of facets, or an alteration of the diamond’s overall shape.

A modified brilliant cut diamond is any diamond that deviates from the standard round brilliant facet arrangement while maintaining brilliant-style faceting.

Grading laboratories such as GIA and IGI use the term "modified brilliant" on certificates to describe diamonds whose facet pattern differs from the traditional round brilliant arrangement. However, modified brilliant cuts do not receive a formal cut grade — instead, they are assessed on polish and symmetry.

While shape refers to the diamond’s outline (round, oval, pear, marquise, etc.), cut describes how its facets are arranged and proportioned. Not all fancy shapes are modified brilliants — only those that use brilliant-style faceting, such as oval, pear, and marquise shapes, qualify as modified brilliant cuts. Step cuts (like emerald or asscher cuts) feature parallel, rectangular facets and are not considered modified brilliants.

Modified Brilliant Diamond Shapes

Oval Diamonds

Elegant and elongating, oval diamonds retain the sparkle of a round brilliant but with a graceful, elongated silhouette.

About Oval Shape Diamonds

Pear Diamonds

Distinctive and romantic, pear-shaped diamonds combine a rounded end with a tapered point, offering a flattering shape.

About Pear Cut Diamonds

Marquise Diamonds

Historic and striking, the marquise diamond has a regal, elongated shape with pointed ends, often appearing larger than other shapes of the same carat weight.

About Marquise Diamonds

Princess Cut Diamonds

MModern and geometric sparkle, the princess cut is a square-shaped diamond with brilliant-style faceting.

About Princess Diamonds

Cushion Cut Diamonds

Soft, pillow-like contours, cushion cut diamonds have rounded corners and a classic feel while maintaining strong brilliance.

About Cushion Cut Diamonds

Radiant Cut Diamond

Rectangular brilliance with clipped corners, radiant cuts combine the sparkle of a brilliant cut with a rectangular shape.

About Radiant Diamonds

A modified brilliant cut diamond features brilliant-style faceting but differs from the round brilliant in facet arrangement, shape, or both. Many fancy shapes like oval, pear, and marquise are examples of modified brilliant cuts.

FAQs

Brilliant cut diamonds: Standard round brilliant with 58 facets designed for maximum sparkle.

Modified brilliant cut diamonds: Retain brilliant-style facets but vary in facet arrangement or shape (e.g., oval, marquise).

Step cut diamonds: Rectangular facets arranged in parallel lines for a hall-of-mirrors effect (e.g., emerald, asscher).

The round brilliant cut diamond sparkles the most, especially when graded Triple Excellent (GIA) or Ideal (IGI), due to its precise facet arrangement.

Marquise, oval, and pear diamonds often appear larger than round diamonds of the same carat weight because of their elongated outlines and greater surface spread. Diamond size comparison chart.

Brilliant cut diamonds are designed to maximize sparkle, with round brilliants being the only shape to receive an official 'cut grade'. A rectangular modified brilliant cut diamond combines the fire of a brilliant cut with an elongated shape, offering a unique blend of brilliance and modern aesthetics. These diamonds feature smaller, angled facets similar to round brilliants, but in a rectangular form. In contrast, step cut diamonds, such as emerald cuts, have larger, parallel facets that emphasize the stone's clarity and produce subtle flashes of light rather than intense sparkle.

It is more difficult to find some diamond shapes than others. The demand for asscher diamonds and radiant diamonds is much lower than for other diamond shapes, making them rarer than most diamond cuts. They are followed closely by marquise and hearts.

Due to many of the reasons already stated, the round brilliant diamond continues to be the most popular diamond shape in the United States. Followed by oval diamonds, pear diamonds, emerald cut diamonds, and cushion cut diamonds.

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Cushion Cut Diamond Rings

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Princess Cut Diamond Rings

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Radiant Diamond Rings

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Round Diamond and Princess Diamonds | Lisa Robin

About Diamond Shapes

Buying a diamond engagement ring means selecting from a variety of diamond shapes — round, oval, marquise, pear, and more. Shape refers to the diamond’s outline when viewed from above, while cut describes how its facets are arranged to reflect light and create sparkle.

For example, the round brilliant cut diamond is the most popular, featuring 57 or 58 precisely arranged facets that maximize brilliance.

Many other shapes — such as oval, marquise, and pear — are variations of the brilliant cut and are known as modified brilliant cuts. A modified brilliant cut diamond retains the brilliant-style faceting of a round diamond but alters its shape or facet arrangement.

All shapes other than round are considered fancy shapes, but only those with brilliant-style faceting (like oval and marquise) qualify as modified brilliant cuts.

About All Diamond Shapes