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The 4th C: Diamond Cut

The fourth of the four C’s in this sequence is the Cut, or shape of a diamond. The shape is important to determine the quality of the polished diamond. The shape a diamond will become depends on the diamond quality and the amount of material loss in the process from rough to polished.

Explanation of the fourth C (Cut) by our Chief Purchasing Officer

Our Chief Purchasing Officer helps you to understand the basics of the 4 C’s of diamond valuation. A more detailed explanation, you find below this video.

Diamond cuts

A good diamond worker can cut a diamond in almost every shape imaginable. However, it is important that the cutter keeps the way the light reflects in mind. There are several preferred cuts: the brilliant, emerald, princess, marquise, pear, heart, oval, cushion, Asscher and baguette.

Brilliant diamond cut

The most popular and common diamond shape is the brilliant cut. Almost 95% of all diamonds are this particular shape. This is because the brilliant diamond has the most value and reflects the light in the best way possible. Another reason a brilliant is so popular is that it is suitable for use in most kinds of diamond jewelry.

Royal 201 diamond cut

The Royal 201 is a patented brilliant by Royal Coster Diamonds. A regular brilliant has already a beautiful sparkle with 57 facets. But the Royal 201 exceeds this on every level. This brilliant has no less than 201 facets. The 201 facets reflect the light perfectly. It makes this cut the most sparkling diamond shape in the world. You can see the difference between a regular brilliant and our Royal 201 during one of the tours at our diamond polishing factory.brilliant cut diamonds

Emerald diamond cut

The emerald cut is named after the well-known green stone that is cut often in this way. The emerald cut has a reputation of a luxurious diamond shape. This is because any small imperfections are highly visible in this kind of cut. Visible inclusions make the diamond less valuable. That's why we use pure and luxurious diamonds for emerald cuts. But they come with a matching price tag. The emerald cut engagement ring is very popular by celebrities such as Kim Kardashian and Angelina Jolie. emerald cut diamonds

Princess diamond cut

The second most popular diamond shape is the princess cut. This square cut with straight lines has a beautiful sparkle. The angular shape makes this type of diamond great for usage in different kinds of jewelry. Princess cuts are for diamond engagement rings, earrings, and bracelets.princess cut diamonds

Marquise diamond cut

Named after the Marquise of Pompadour (the mistress of Louis 14th) is the marquise cut. The pointed ends of this cut optimize the light reflection within the diamond. But they also make the diamond to appear bigger. The marquise is almost exclusively used in rings, sometimes combined with small stones surrounding it. marquise cut diamonds

Pear diamond cut

We know the pear cut or pear-shaped diamond also as a teardrop diamond. This cut looks like a combination of the round brilliant shape and a marquise. The pear-shaped diamond is loved because of its elegant look. A pear-shaped diamond on a ring makes the finger appear longer. In earrings and necklaces, pear cut diamonds are also very popular because they accentuate the length of the neck.pear cut diamonds

Heart diamond cut

The heart-shaped diamond is a variant of the pear cut. It is perhaps the hardest diamond shape to create because it takes advanced skills to create symmetry. It’s no secret that a heart stands for love and that diamonds are the international symbol for love as well. Therefore, heart-shaped diamonds are very popular gifts. You can find heart shapes in any kind of diamond jewelry.heart shaped cut diamonds

Oval diamond cut

Oval diamonds have a reputation of prestige and luxury. This is because many famous diamonds are cut in an oval shape – the Koh-I-Noor for example. But also women with short or wide fingers often prefer to wear oval diamond rings. Because the oval shape makes the fingers look more slender; in contrast to for example the brilliant cut. This gives an overall more luxurious look. Moreover, in terms of sparkle, the oval diamonds come closer to the round cut than any other shape. Little of the brilliance is lost. oval cut diamonds

Cushion diamond cut

The cushion cut is sort of a combination of the princess and oval cut. This diamond shape is often described as a rectangle or square with rounded corners. The cushion-shaped cut is over 100 years old. Especially in the 19th century, it was very fashionable. In 1930, the shape became popular again. Nowadays we consider the cushion cut diamond a classic and romantic shape. It distinguishes from modern polishing techniques. cushion cut diamonds

Radiant diamond cut

Like the princess, the radiant cut is a square shape. But like the cushion diamond, the radiant has round corners. The way the radiant is cut is similar to the emerald cut, combined with the way facets are created on a brilliant. The radiant has no less than 70 facets. You could say the radiant is actually a combination of many different cuts. In recent years the radiant became increasingly popular in diamond engagement rings. Often these are solitary rings. radiant cut diamonds

Asscher diamond cut

The Asscher cut originates from Dutch soil. In 1902 the Asscher brothers cut a square diamond the same way an emerald is cut. This way, they created a completely new diamond cut. Due to the large square table (top of the diamond), the color and clarity of the diamond are beautifully shown. Asscher cut diamond

Baguette diamond cut

Like the cushion diamond, the baguette is also a ‘fancy cut’. This cut was especially popular in the Art Deco period. Baguettes are rarely the main stone in any diamond jewelry. They are often placed to the center stone. baguette cut diamonds

The standard

Each cut has its own standard. The closer the cut is to the standard, the better it is qualified and the higher the value of the diamond.

The diamond is qualified as:

  • Good
  • Medium
  • Poor

The standard for the brilliant is as follows:

  • size of the table: 56% of the girdle
  • the height of the crown: 11-17% of the whole and at an angle of 34.5°
  • Size of the girdle: very thin to medium
  • corner pavilions:

If a brilliant cut meets the requirements above, its gets qualified as ‘good’. When a diamond is grinded badly, this can lead to a loss in value of 6 to 15%. For bad cuttings even more! A diamond with poor grinding gets therefore qualified as ‘poor’.

ideal brilliant cut

The sparkle

It is important that the diamond polisher cuts the angles of a brilliant at a proper degree. The angles relate to the reflection of light within the diamond. When the corners are too steep, light gets out from the sides. But when the corners are too flat, the light continues to reflect until it decays in dead corners. The light is lost and leaks through the bottom of the crown. If the diamond has a proper cut, the light reflects in the ideal way. It travels through the table, the pavilions and the bezels of the top straight up. This creates an unsurpassed, perfect brilliant sparkle.

The weight lost

A rough diamond looks like a chunk of white or colorless stone. It does not sparkle, or at least not a lot. During the polishing process, we lose about 60% of the raw material. This is due to the sawing of the stone, the cutting, the grinding, and the polishing. This may seem like a waste. But because of the grinding loss, the diamond becomes even more beautiful and valuable. This principle led to the saying: "everybody wants to be a diamond but few are willing to get cut". rough uncut diamonds


The finished cut affects the price. The cutter must ensure that the facets are beautifully ‘sweet’. This means that the facets have no cutting stripes and have a nice smooth finish.

All diamond cuts are possible

Besides the best-known diamond cut, there are a lot of other shapes possible to cut a diamond into. Our diamond cutters have truly mastered the art of diamond polishing. You can see them creating diamond cuts in a Royal Experience tour and learn more about the 4 C’s of diamond valuation. Our experienced guides love to tell you everything about the 4 C’s as well. Do you want to cut a diamond yourself? Assign for our Diamond Masterclass. You’ll learn all there is to know about diamond cutting.

The other C's:

> The first C, Carat
> The second C, Color
> The third C, Clarity