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Source of the Sparkle: Understanding Cut and Shape of a Diamond

Marquise. Square. Emerald. Brilliant. Glittering diamonds are cut into a seemingly innumerable number of shapes. The perfectly-faceted stone that is set into a ring or necklace is a far cry from the “rough,” or mass of gemstone, that is initially unearthed in a mine. Upon receiving a rough stone, a bench jeweler must use precise artistry to decide how best to cut and shape the gem in order to achieve an ideally-cut stone in terms of size, clarity and color.


While the words “cut” and “shape” are often inextricably linked and used interchangeably, they are, in fact, completely different terms that signify isolated aspects when it comes to diamonds and gemstones.


When done correctly, the cut and shape can completely transform the value and quality of the final diamond. This article will delve into the fascinating differences between cut and shap and will teach you how to distinguish between the two.


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8.45-carat White Diamond Round Brilliant Shape, Excellent Cut Grade

8.45-carat White Diamond
Round Brilliant Shape, Excellent Cut Grade


Diamond Cut: Why It's Important

A gemstone’s primary purpose is to be beautiful, and cut is a critical factor that determines a stone’s overall beauty and allure. The importance of a gemstone’s cut lays in its ability to dazzle and shine. Proportions, facet patterns and symmetry can all be manipulated to maximize the sparkle of a stone, which ultimately increases its value.


One of the 4Cs of diamond grading, a diamond’s cut helps to determine a stone’s overall quality grade. Of all the quality factors, “cut” is often the most difficult and complex to analyze due to the number of variations between cuts and stones. While the type of cut is important, what really matters in terms of a diamond’s cut grade is how well its facets interact with the light.



10.06-carat Fancy Blue Diamond Ring

10.06-carat Fancy Blue Diamond Ring


Ultimately, a diamond’s cut is graded based on seven different factors. The first three involve the most important visual effects for a diamond:



    • Brightness - total light refracted from a diamond


    • Fire - the dispersion of white light from a diamond into the spectral colors


    • Scintillation - the amount of sparkle a diamond produces


The remaining four factors include weight ratio, symmetry, polish, and durability.


How Cut Influences Quality

Often, you may hear stones referred to as “well-cut.” What does this exactly mean and what are the tell-tale signs? A well-cut diamond is one that both accepts and returns light to the greatest possible degree. In other words, it is a stone that is so symmetrical and proportional that it “faces up” with the highest amount of brightness and fire.  The overall beauty of a diamond depends more on the cut than any other factor. Although it is extremely difficult to physically tell the actual cut of a diamond, a way to know that diamond has an optimal cut is through its sparkle and shine.


Well-cut diamonds tend to command the highest premiums on the jewelry market. On the other hand, a poorly cut diamond is one whose facets cause light to leak through the sides rather than refracting it upward, resulting in a dull, weak appearance. Although it may be a popular choice for shoppers to go down in quality to get a larger ring, it is still important to note that the overall brightness, fire and scintillation will all be compromised.


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The Two Main Types of Cuts in Diamonds

While a diamond can be cut in a variety of ways, the two most popular forms are the brilliant cut and the step cut. Before the diamond can be cut and formed, the connoisseur will consider the size and shape of the rough diamond and choose the cut that will produce the greatest final product. Once these factors have been considered, they will then proceed with either the step or brilliant cut. In most cases, an octahedral diamond will be turned into a brilliant cut, while the twinned shaped diamond will be turned into other shapes.


The step cut is when a diamond’s facets are aligned parallel to one another. This cut is usually round or rectangular in shape. These diamonds are known for having excellent clarity with a minimal look. A few common styles of fancy cut diamonds include the Asscher, Baguette, and Emerald.


A brilliant cut diamond is a cone shaped stone that has numerous facets for optimal brilliance. Due to its large surface area, more light can reflect through the diamond, leading to greater sparkle and shine. Common styles of the brilliant cut diamond include cushion cut, pear, round, and oval.


What Are the Different Shapes of a Diamond?

Unlike a stone’s cut, which depends on its facets, a stone’s shape refers to the silhouette of the stone. While the diamond’s cut can ultimately help to determine its shape, different shapes can be cut in different ways.  While different shapes may be chosen to maximize the clarity and color of a stone, it is also a matter of the personal preference of the stone’s connoisseur.


The shape of the diamond is one of the easiest ways to distinguish one diamond ring from another. While there are popular shapes with rounded edges or a rectangular cut, there are also more unique shapes such as the pear or heart. Generally speaking, the round brilliant diamonds are known to be the most expensive shape you can find due to its impeccable quality and brilliance. Below are some of the most popular shapes for diamond engagement rings and estate rings.


Popular Shapes




The most popular is the round shaped diamond, or brilliant cut, which is popularly used in engagement rings and pendant necklaces. Though this shape has existed since the 1700s, it is today often called a round brilliant as the angles it commands enhance the diamond’s brilliance to the greatest degree. The shape of this diamond allows for maximum light reflection, giving it a sparkle that outshines the rest.


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8.45-carat White Diamond Round Brilliant Shape, Excellent Cut Grade

8.45-carat White Diamond
Round Brilliant Shape, Excellent Cut Grade



Named in 1745 for Louis XV’s mistress, Madame de Pompadour, the slender and elongated shape of the marquise diamond was said to resemble the mistresses’ lips. Overtime, this shape has prevailed as one of the most popular diamond shapes today. Due to its length, it creates an illusion that a diamond is larger than it is. Each point on either end of the marquise cut diamond must align perfectly, making symmetry of the greatest importance for this shape.



8.03-carat Marquise-Cut Diamond Ring

8.03-carat Marquise-Cut Diamond Ring



The oval shaped diamond is most often selected due to its ability to elongate and slim the wearer’s fingers. The shape was revitalized and popularized in the 1960s, though first mention of an oval cut shaped diamond has been found as early as the 14th century. In fact, some of the world’s best-known stones, such as the Koh-I-Noor, are fashioned into an oval shape. Other notable oval diamonds include those worn by Queen Victoria in the late 19th century.



Fancy Pinkish Purple & Yellowish Green Diamond Ring, Center Diamond is an oval shape

Fancy Pinkish Purple & Yellowish Green Diamond Ring, Center Diamond is an oval shape



Often referred to as a teardrop, the pear shape diamond has existed since the 1400s and touts an appealing silhouette with gently rounded sides (shoulders and wings) terminating in a single point. Like the marquise, symmetry is of the utmost importance for this shape as the sides and the point must be ideally aligned.



Fancy Yellow and White Diamond Bypass Ring, comprised of two pear-shaped stones

Fancy Yellow and White Diamond Bypass Ring, comprised of two pear-shaped stones



Like the round shaped diamond, the square shape (or “princess cut”) is a popular stone for diamond engagement rings. With its square silhouette and shallow crown, the shape reflects light in a different, though no less brilliant, way than round shaped stones. The shapes bold lines, however, give it a more modern, contemporary appearance.


Browse our hand-picked collection of fine diamond estate jewelry and antique diamond rings.


Whether you go for a unique shape diamond or one with a classic appearance, the choice is yours. With such a wide variety of stones to choose from, you'll be able to find the most perfect diamond for a special gift or an engagement.


Still don't know which type of diamond is best for you or your special someone? Visit our showroom or call one of our experts at M.S. Rau Antiques today.



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