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Likely the most misunderstood of the 4 C's, learn everything you need to know about cut.

All About Diamond Cut

While every bit as important as the others, perhaps, none of the 4 “Cs” of diamonds is more widely misunderstood than cut.

Many people confuse cut with SHAPE; however, they are not the same thing at all. Here we will address both and elaborate on the choices available to you.



As its name implies, SHAPE refers to the choice of silhouette or outline of the diamond.

Round often referred to as Round Brilliant, is the most popular diamond shape sold today across all jewelry categories. More than half of engagement rings feature round center diamonds. This shape has been around since the 1700s but has been modified numerous times until in 1919, Marcel Tolkowsky determined the ideal placement, percentages, and angles to achieve maximum brilliance. Only round diamonds are assigned cut GRADES as there are no universally accepted standards for other shapes.

The Marquise shape reportedly received its name back in 1745 from the Marquise de Pompadour, the mistress of King Louis XV of France. Some people believe the long, narrow shape makes the diamond look larger on the finger. Symmetry is particularly important in this cut for the best possible appearance.

The Oval shape is perhaps the oldest know diamond shape. First mentioned in the 1300s, the world-famous Koh-I-Noor diamond in the British Crown jewels is an example of an early oval shape. This shape makes the finger look longer and slimmer and the proportion of width to length is a personal preference.

The Pear shape also originated as far back as the 1400s. This style should have the point facing the end of the finger for a lengthening and slimming effect.

The Heart shape diamond is a popular symbol of love and romance. A skilled cutter keeps a close watch on the diamond’s symmetry and polish.

Here’s where it can get a bit tricky. Princess, cushion, radiant, and asscher are all either square or rectangular shapes, however, they are all their own individual cuts. For example, the first example below is square-shaped but referred to as a princess-cut.

The Princess cut, a modern design originating in the 1980s. These diamonds always have the prongs set at the four corners for maximum protection during wear.

The Cushion cut has a square look but with rounded corners like a “cushion”. Most common in the early 20th century, older versions are highly prized in antique jewelry of that period.

The Radiant cut, developed in the 1970s, is a dazzling and vibrant choice that makes an exciting and unique center stone for an engagement ring.

The Asscher cut, developed in the early 20th century, was popular in Art Deco jewelry. With some modern modification, the cut began a revival in popularity in 2002.



How skillfully a diamond has been cut determines whether it can achieve its best possible brilliance, scintillation, and fire. This is the basis for how the cut GRADE is determined when one is used.

That is because there are no universally accepted standards for other shapes; only round diamonds are assigned cut grades. All shapes, other than round, are referred to as “fancy” shapes in the diamond trade. If you seek to compare the quality of cut of one fancy shape such as an oval to another oval, we suggest you look at the diamond report by IGI.


This is available for all diamonds sold by Clean Origin. On that report, you will see the terms “symmetry” and “polish”. These also exist on round diamond reports but are especially significant in the absence of a cut grade. A grade of “good” or “excellent” here indicates that the shape is of a pleasing length to width ratio and that the final polish on all the facets allows for maximum sparkle in the cut you have chosen.

Before explaining the differences in cut grade, it should be noted that “cut” is the most difficult of the 4 Cs for untrained people to see. The visible difference between cut grades, while scientifically accurate, is minimal in mounted appearance for the better grades sold by Clean Origin. In selecting any diamond, the best choice will be a mix of optimal color, clarity and cut that appeal to the individual buyer.


Now let’s take a look at the parts of a diamond and the names used to describe them:

The precise placement of the various diamond facets (flat surfaces) and their relative size to the entire surface area determine which grade a diamond receives. Depth, girdle thickness, and size of culet are also considered.

The meaning of each grade as certified by the International Gemological Institute (IGI):

Ideal – IGI certifies that this is a diamond cut to such exacting proportions that it achieves maximum scintillation and fire with a perfect mix of light and dark areas.
Excellent - Diamonds with this grade have an even pattern of light and dark areas making their brilliance and fire exceptional.
Very Good – While no individual proportions or angles cause this diamond to “bad”, a combination of factors makes the stone slightly darker than one graded as excellent.
Good – A diamond with this grade would have somewhat less scintillation or fire but still be quite lovely.

While diamonds of lower grades do exist, Clean Origin does not sell those.

The terms we use on our site are universally understood throughout the diamond business. However, you may see grades using differing terms or even ones like “Super Ideal” from other web sites or retailers. If you don’t know what those mean, don’t worry, neither does anyone else but the company that made them up. They are proprietary to the company that uses then and are not universally accepted terms in the diamond business. In other words, they can mean whatever the users want them to mean.

At Clean Origin we also offer some round diamonds in the “Hearts and Arrows” style of cut. Preferred by some customers, this style of round brilliant cut offers a very precise cut for maximum brilliance and with 10X magnification, a pattern of “hearts and arrow” shapes may be seen. Please note: All Hearts and Arrows diamonds are ideal cut but not all ideal cut diamonds exhibit the hearts and arrows pattern. Some people have a strong preference for Hearts and Arrows but the decision is yours.

Always remember when selecting a diamond, find the diamond that is a perfect choice for you. That is both a balance of the 4C’s and a cost that is comfortable for you. These elements will determine your perfect choice in diamonds.



Why is there no cut grade for my princess cut diamond?
Princess cut diamonds (along with all other shapes except round) are considered “fancy” shapes and there are no universally accepted standards for that cut, therefore, no cut grade would be meaningful. If you are comparing stone, we suggest you pay attention to the polish and symmetry shown on the IGI certificate. That will tell you how well the stone was polished to improve the sparkle and how pleasing the proportions are of the stone.

Does having the diamond laser inscribed lower the cut grade?
No. The inscription of the certificate number has no effect on any diamond grade but helps to positively identify the specific stone and match it to the certificate issued. This laser inscription is common on all diamonds, both lab-grown and mined.

What is the “bow-tie effect” and will my diamond have that?
The so-called “bow-tie effect “occurs when there are two particular facets where light is not as well refracted as others in a diamond. This happens normally in all Ovals, Marquise, Heart and Pear shape diamonds. This is a direct result of the shape and does not negatively impact the diamond’s value.

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