Cut - The Size of the Diamond

The size of the diamond or cut is part of the 4C of the diamond. The cut is very important because it is elle that allows the diamond to be so brilliant. It is also the only one of the 4C made by man. The cut is made by skilled craftsmen called lapidaries. Their job is to cut the stone to bring out the "fire of the stone", its brilliance and beauty.

It is sometimes difficult to understand that the brilliance of the diamond does not depend on its carat but on its cut which is technical, measurable and adjustable to maximize the brilliance of the diamond

Brief history of the modern brilliant cut diamond:

- In 1919: Marcel Tolkowsky, a physicist and mathematician, discovered the ideal proportions of a diamond. This cut is considered the basis of the modern cut.

- In 1966: Tillander, a lapidary, published the standards of the Scandinavian standard. This nomenclature serves as the basis for the modern cut with table/crown/facet proportions slightly different from the standards stated by Tolkowsky.

- In 1978: IDC (International Diamond Council) defined the standards that give the diamond the most refraction. These standards are the combination of the professional experience of diamond dealers and scientific knowledge in the field of optics.

You should remember that the cut of the diamond only refers to the proportions of round gems.

Fun Fact: The ideal proportions of the diamond

- The table: the upper horizontal facet of the diamond. (Fun fact: usually the one you see first at a glance)

- Culet: the lower part of the diamond

- Crown: the upper part of the diamond

- Girdle: the central part of the diamond, a narrow section separating the crown from the pavilion and serves as the setting edge of the diamond

- Colette: the small facet at the bottom designed to prevent chipping and at the tip

- Star: it's the table + the triangular facets all around that form a star.

- Bezel or table corner: facets between the star and the half

- Half: facet between the bezel and the girdle

Why is the size of the diamond-elle important?

A well-cut diamond will reflect more light. This action will have a positive effect on the stone, it will appear larger than it actually is and will have greater brilliance, fire and scintillation. The cutter can also make sure to camouflage certain inclusions (internal characteristic resulting from the crystallization of the stone).

To put it simply: the Cut is THE thing that allows the diamond to be even more beautiful. You can have the largest diamond in the world, if its cut is neglected, it will not be at its maximum qualities.

You have just read technical and difficult to understand terms for the diamond. Know that:

The fire of the diamond corresponds to the dispersion of light, it is the power of the diamond: to act like a prism.
The brilliance of the diamond is the light reflected in and out of the diamond. Perfect proportions are designed to prevent light leakage and therefore make the diamond more brilliant.
The scintillation of the diamond is the play of facets that sparkle intensely when the diamond moves.

Actually, it is easy to see the difference between a diamond cut in ideal proportions and a diamond cut with an inferior cut.

In this photo, we can clearly see its importance. On the left a diamond cut in ideal proportions, on the right a diamond cut with an inferior cut. We can clearly see the difference in brilliance, fire and scintillation.

Another important factor in the cut of the diamond is the angle of the pavilion (which is the lower part of the diamond). This factor affects the quality of the reflection of light towards the viewer. If the angle is shallow the light will reflect downwards and not towards the table of the diamond. Therefore, to the eye, the diamond will be less brilliant. This diagram will help you better understand the importance of the pavilion angle.

The size of the gem has a real impact on the brilliance of the diamond, that's why it is important and should be a priority when choosing a diamond.

Why aren't there only excellent diamonds?

These diamonds exist for various reasons. Many people will pay more attention to the carat weight of the diamond even though it is not the most important thing, we explain it in our guide on the carat, here. But this craze for carat weight does not decrease so prices increase significantly for a larger carat than for a better cut. Thus, quite a few lapidaries will prefer to keep weight on the stone rather than cut it in ideal proportions which will certainly make it lose carat weight.

And for this weight preservation, the cutters will produce a deeply cut gem but you now know that this will have an impact on the brilliance of the diamond. But if these craftsmen do this, it will increase the carat weight and consequently the price.

Another obvious reason that forces lapidaries to cut the diamond differently is the presence of inclusions. Inclusions can be more or less large, so the cutters will cut the inclusion and this sometimes results in not having the best possible cut, but favoring purity.

How to recognize diamond cuts and which shade to choose?

When you buy a diamond, it is essential that it comes with its ID card: the certificate. The certificate is made by independent laboratories such as GIA, IGI, HRD... On these certificates there will be information about the size of the diamond.

The size is classified into 5 categories:

Excellent / Ideal cut: this is the size with perfect proportions, the top of the diamond cut. Elle maximizes the brilliance. However, gems of this size generally have smaller tables but are adorned with a perfect dispersion of light or fire.
Very Good: viewed from top to bottom, these diamonds may have an asymmetrical pattern of dark and light spots. These diamonds may also have a dull appearance.
Good: these diamonds do not reflect light as much as the higher grades because their fire, their brilliance and their scintillation are not up to par.
Fair: this cut does not necessarily retain the light that enters the stone, so the fire and brilliance are reduced.
Poor: this diamond size is dull even to the naked eye. It is a bad value for money.

(Fun fact: The GIA has classified diamond sizes as above, but beware, there are other rankings almost equivalent to that of the GIA. This is an important thing to know, because, two diamonds can share the same rating, but do not necessarily have the same appearance.)

For the choice of a diamond, it is best to prioritize the cut over the color and clarity. Ideally, the diamond size should be excellent or very good. But if you have a tight budget, good diamonds may be the right solution.

Remember that a perfectly cut diamond therefore excellent will often be smaller than a good or fair diamond.

How do you cut a diamond?

As you've understood, the size of the diamond is very important. The steps of the cut must be meticulous and delicately carried out. Before cutting, a laser is used to cut the rough diamond and then cut all the shapes that are desired. (Fun fact: this is an Israeli technological specialty).

What are the steps in cutting a diamond? There are 5 key steps:

Cleaving: involves splitting into two or more pieces to have a "suitable" shape for the next step.
Sawing: involves cutting a stone into two parts that will be faceted or roughed. There are two directions of sawing, horizontal and vertical. The advantage of sawing is that it allows to separate into two metals that cannot be cleaved.
Roughing: this is the step that serves to round the diamond. It is used to prepare a draft of the final size.
Faceting: this means that a defined number of faces will be made on a rough stone, they have a defined degree of inclination. The lapidary rubs the stone against a polishing disc and starts with the table because it serves as a base reference. The symmetry of the facets is important.
Polishing: is carried out on the same cast iron disc as the faceting but with a finer diamond powder. Polishing is important because if it is bad, it leads to a depreciation of the diamond.

1. The main cutting centers in the world are in Bombay, Antwerp, Tel Aviv, New York, China and Russia.

2. The external characteristics of the diamond or imperfections are caused by man during polishing if it has been poorly done.

3. A more sparkling, radiant and brilliant diamond will often be smaller than a diamond that will be a little less sparkling.

Advice from the diamond dealer:

The size of the diamond is a very important factor in choosing a diamond. It should not be overlooked and is essential to understand.

You can compromise on the color and clarity of the diamond, but not on its cut! Elle is crucial to bring out the best in the stone.
Prioritize an excellent or very good cut if you want the maximum brilliance, fire and sparkle on your diamond. But if you don't have the budget, choose a good diamond.

Congratulations! You are an expert in understanding diamond size, don't forget to demand the certificate of your diamond when the chosen diamond is certified.