What Is a Diamond Cut?

Before we get into the importance of the diamond cut for ideal diamond proportions, let's first know what a diamond cut actually is!
Diamond Cut is mostly thought of as the shape of the diamond, which are usually round, heart, oval, etc. In your search for the perfect diamond you will often see the terms ‘cut’ and ‘shape’ used interchangeably in their descriptions. However, that's not what a diamond’s cut actually is.

The diamond cut represents how well a diamond reflects and refracts light. After all, a diamond is known for its reflective properties and its shiny surfaces. If a diamond can't do that properly, it's value goes down and so does its demand. To do so the diamond needs ideal proportions which I will show you below.

So diamond cut has huge significance in the diamond's price and its demand.

What Are GIA Grades?

Usually, when you hear about diamond cut, you also hear about GIA grades. GIA grades diamonds on the basis of their quality of cut. Round diamonds are the most famous amongst consumers, and GIA has divided them into five categories based on their cuts, starting from Excellent to Poor. You would want to buy excellent diamonds because they are the most beautiful and reflective ones. Hence "excellent" or "very good" grades are the first hint to ideal diamond proportions.

The following table should give you a brief overview of GIA Grading:

Excellent Optimal level of fire and brilliance because almost all of the incoming light is reflected by the diamond. The result is a beautiful sparkle.
Very Good High level of fire and brilliance. To the naked eye the sparkle is close to excellent but there could be patterns of dark spots in the diamond from the top view.
Good Less light then the better graded cuts is reflected by the diamond. This leads to less sparkle and a lower price. You can see the difference with the naked eye.
Fair The fire and brilliance is significantly reduced. Most of the light is not reflected but lost through the bottom and sides of the diamond.
Poor There is no fire, brilliance and no sparkle. The light is completely lost through the diamond. These cuts are not worth it.

I suggest that you go with excellent or at least very good graded diamonds. They may seem a little expensive at first, but these diamonds are worth every penny you spend.

Factors Affecting The Quality Of Cut

There are many factors that affect the quality of cut and thus determine the price of a diamond.
These factors include:

  • Proportions, which refer to the table, width, and depth of a diamond.
  • Symmetrical facets, which refer to the mirrors, windows, and steps of a diamond.
  • Brilliance is the brightness of white light after it is reflected by a diamond.
  • Fire is the dispersion of light into many colors after being reflected by the diamond.
  • Scintillation is the measure of the flashes of sparkle when a diamond is moved.

I won't go into detail of every factor but I will discuss the depth, width, and table of a diamond because these are mostly concerned with how light is reflected by a diamond and hence, are leading to ideal proportions for a diamond.

Diamond Proportions

Ideal Diamond Proportions

Diamond Depth

Depth is the measure of the height of the diamond and comparing it with the width to get a specific number.
There are three depths: Shallow, Ideal, and Deep.

Ideal Diamond Proportions - Cut Quality

If your diamond is shallow, it will not reflect light to its base and thus make the experience very dull. The same goes for deep diamonds, which also reflect the light to the side. Ideal depth ensures that the light is reflected to the table with exquisite style.

Diamond Table

The diamond table is the flat top surface of the diamond, which allows the reflected light to pass through it. Unlike Diamond depth, there aren't types of the diamond table; however, an ideal diamond table is recommended if you want to see the exquisite light escape from the diamond.
If the table is too wide, it won't allow the light to diverge into many colors. And if the table is too narrow, it won't allow the light to pass through it.
An ideal diamond table would not only allow light to diverge but also reach the eye without any problem for sparkling effects!

Diamond Width

Diamond width, as the name suggests, is the width that a diamond has (pun intended).
It is a very important factor in determining the grade of the diamond as the width to height ratio allows us to know how well a diamond will reflect light into the viewer's eye. So consider these factors when buying a diamond!

Depending on the composition of these three proportions the diamond cut will go from "good cut" to your adorable ideal diamond proportions if everything hits the maximum.

Diamond Cut Versus Diamond Quality

Diamonds are sought after because of their ability to catch and refract light in a dazzling display of hues and sparkle. Most people will think of a diamond’s cut as its final shape, which includes round, pear, marquise, heart, and oval.

However, the amount of sparkle a diamond can produce depends heavily on how well the facets can catch and transmit light.

It takes skill, experience, and a practiced hand to get the most out of a diamond. Also essential to the skill is the ability to look at a stone and understand how to proportion the facets so perfect symmetry is achieved. 

With the knowledge of how complicated it is to cut a diamond it's consequential that a better cut and a higher quality leads to a higher price.

How The Quality of A Diamond’s Cut Affects the Price

Diamond pricing relies on many different variables that make it quite a complicated task. The carat of a diamond has the most weight in determining its value because it’s one feature in which most consumers have at least a basic understanding. There’s a lot more to pricing a diamond beyond its carat value, though.

While a diamond’s carat will influence the price, the cost will go up when the cut quality improves. Parts of the diamond need to be removed during the cutting process, and higher quality cuts achieve more elegant proportions and more sparkle.

Removing more of the rough diamond material means a reduction in carat weight but is usually accompanied by an increase in price. Loss of carat weight is a necessary sacrifice for higher quality cuts, and the higher rates compensate for that.

Unfortunately, not every piece of diamond rough that passes under a jeweler’s loupe is going to make the ‘cut.’ Some of the pieces will not have the quality needed to produce a finely cut diamond that can be sold for a profit.

For this reason, many discount jewelers are selling poorly cut diamonds that are priced more on their carat weight than their ability to sparkle and shine.

Types of Diamond Cut

When talking about diamond cuts, many people sometimes gloss over types of diamond cuts. However, these cuts have a huge part in determining the quality of the diamond you get. Broadly, diamond cuts are divided into three types, namely Step Cut, Brilliant Cut, and Mixed Cut. Let's discuss each one in more depth.

The classic round diamond (check out online) is the most popular choice for lovers of jewelry and is renowned for its high level of brilliance. Every other diamond shape on the market is a ‘fancy’ shape with people drawn to the elegance created by their unique facet layouts.

Step Cut

Some of the simplest diamond cut designs are created using the step cut. Good examples of a step cut with which most people will be familiar are the rectangular or emerald shape designs (check out online), and to a lesser degree, the Asscher cut (check out online).

Ideal diamond proportions Round Cut

If your goal is to display refined class and opulence, then a step cut diamond makes the perfect choice. The tables and culets are broader, while the rest of the facets are softer and more subtle.

Facets are created parallel to one another for a pleasing geometric design that highlights the diamond's interior, without any of the distraction of sparkle and brilliance created by some of the other cuts.

The step cut is most often used when preserving carats is the dominant factor in the design. As discussed, many of the other cuts in this list almost demand that a significant portion of the diamond be discarded to bring out more of the diamond's sparkle.

Diamond designs using the step cut became quite popular during the early 20th century. It seems that jewelry featuring the simpler aesthetic of geometric design was all the rage. The less complex cuts were also more simply matched with other jewels that were popular at the time.

Because step cuts cannot rely on their brilliance for their appeal, the diamond cutter must base his choice on the diamond's luster and clarity. The interior of a step cut is the highlight of its design, so strong polish is essential. 

Brilliant Cut

This type of cut is the most reflective in nature due to internal refractions.

A brilliant cut diamond has been cut in a way to produce many facets, because these are responsible for creating the refractive brilliance of a high-quality diamond.

A brilliant cut diamond usually has a round or cone shape, with bright rays of light bouncing around inside the top of the diamond that make them well suited for engagement rings and other displays where flamboyancy is the order of the day.

Brilliant cut techniques have evolved from the old European cut (the circular brilliant to the modern brilliant). The evolution of brilliant cut diamonds is why we have such distinctive styles of diamonds relative to the age in which they were created.

By the late 1700’s, diamond cutters had honed their craft and developed brilliant cuts in many different sizes and variations, including table size, culet size, crown height, depth, and the length of the facets featured on the lower half of the diamond.

Mixed Cuts

As the name suggests, mixed cut diamonds are created using a mix of different cuts. The goal of creating a mixed cut diamond is to capture the sheer brilliance of a brilliant cut but with the addition of the more interesting designs of shape or step cuts.

Mixed cuts first became popular during the 1960’s but aren’t strictly a new type. Rather, they take the best aspects of the above cuts, and combine them into new and interesting designs.

Heart Diamonds (check out online) are the most prominent example of mixed cut diamonds because it’s one of the most distinctive and is the universal symbol for love, devotion, and romance. A heart shaped diamond cut will feature between 56 and 59 facets to give it exceptional brilliance. Only the best diamond cutters can perfect a heart diamond’s cut due to its complexity, so always expect to pay a little more.

The princess cut (check out online), or square modified brilliant is another popular example of mixed cut diamond – especially in engagement rings. The name dates to the 1960s, but the first princess cut did not arrive until Betazel Ambar and Israel Itzkowitz created it in 1980.

When viewed from above, a princess cut diamond has a square or rectangular appearance. When viewed from the side, the design has more in common with an inverted pyramid with four beveled sides.

The success of the princess cut has prompted the American Gem Society to introduce grading standards that are on par with the stringent quality demanded of round brilliants.

At a Glance

That is a difficult questions because it depends on your needs. Let's say the most important factor is the cut quality of the diamond proportions: Table, Width, Depth. These ones will influence the dimension of sparkle and shiny surfaces.

The GIA grades for diamond cut are:

poor, fair, good, very good, excellent.

I suggest to go with very good or excellent.

Definitely yes. It's one of the major parts affecting the price but also it is very hard to see an excellent cut with naked eyes. Therefore you have to be very careful that the retailer will not sell a poor cut to you for a higher price. Only buy diamonds with official GIA or AGS grades!

There are 3 types of a diamond cut: 

Step Cut, Brilliant Cut and Mixed Cut.