The Essential 4C's
Type of Diamond Cuts
Introduction
Currently most laboratories only provide cut grading for round diamonds as it is harder to assess the ideal proportions for fancy shape diamonds. The only laboratory that currently provides cut grades for fancy shaped diamonds is the less well known AGS, which introduced a Princess cut grade in 2005 and an Emerald cut grade in late 2006.
Based on existing values for the round brilliant and extensive research, LV’57Diamonds has devised a table of recommended proportions for fancy shapes below. Please note these values are only to be used as a reference or guideline. We have grouped the shapes according to their cut classification type (brilliant, modified brilliant, step and mixed cut).
Modified Brilliant Cuts
| Princess Cut | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 62 to 73 | 60 to 77 | 57 to 83 | 55 to 84 | >56 or <84 |
| Table % | 57 to 72 | 55 to 75 | 54 to 80 | 52 to 85 | >52 or <85 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
The ideal proportions of table and depth are much higher for a Princess than for a round brilliant cut. On a GIA certificate, the technical name for a Princess cut is a modified square- or rectangular brilliant cut. It can have the same number of facets as a round diamond (57), but may have as many as 76 or even up to 144.
To read more about the round princess cut, please click here
| Radiant Cut | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 62 to 68 | 58 to 70 | 57 to 75 | 56 to 80 | >56 or <80 |
| Table % | 58 to 65 | 56 to 70 | 54 to 75 | 53 to 79 | >53 or <79 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Oval Shape | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 58 to 64 | 57 to 66 | 56 to 68 | 46 to 71 | >46 or <71 |
| Table % | 55 to 62 | 53 to 64 | 52 to 65 | 50 to 70 | >50 or <70 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Pear Shape | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 58 to 64 | 57 to 66 | 56 to 68 | 46 to 71 | >46 or <71 |
| Table % | 55 to 62 | 53 to 64 | 52 to 65 | 50 to 70 | >50 or <70 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Heart Shape | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 52 to 60 | 50 to 62 | 45 to 65 | 40 to 69 | >46 or <71 |
| Table % | 55 to 62 | 50 to 62 | 52 to 65 | 50 to 70 | >50 or <70 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Marquise Cut | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 58 to 64 | 57 to 66 | 56 to 68 | 46 to 71 | >46 or <71 |
| Table % | 55 to 62 | 53 to 64 | 52 to 65 | 50 to 70 | >50 or <70 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
Beyond the most popular Princess cut, Modified Brilliants come in a range of other shapes. The Radiant cut, which can be square or rectangular usually comes with 70 facets, whilst the Oval (which is in effect an elongated round) often has 58 facets. Other shapes include a tip formation such as the Pear shape (56-58 facets), Heart Shape (usually 56-58 facets), and Marquise (56-58 facets).
Other factors to take into account for Modified Brilliant Cuts include:
Bow tie effect: Some fancy shape diamonds have two black triangles across the middle of the diamond that look like a bow tie. Although bow ties are normal in some fancy shapes, a bow tie that is too big diminishes a diamond’s beauty. Depending on the size, angle and placement of the diamond’s facets, this bow tie can be barely visible (‘minimal’) or very pronounced. It occurs from the variations in the pavilion facet angles which are longer than they are wide which results in a small amount of light leaking through the diamond. Facets are suppose to alternate between light and dark as the diamond, viewer or light source are moved but with the bow tie effect, certain facets stay relatively dark regardless of the movement.
Girdle Thickness: Girdle width varies considerably more in fancy shapes than in the round brilliant. For example, the marquise, pear and heart cuts shapes tend to have thick girdles or are extremely thick at the tips, or in the cleft of the heart shape. The princess cut, on the other hand, which has square corners, may have an extremely thin girdle. It is generally recommended to avoid extremely thin or thick girdles to avoid chipping at one extreme and retaining excessive weight to the detriment of the size of the diamond.
Step Cuts
| Emerald Shape | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 58 to 65 | 55 to 70 | 52 to 75 | 50 to 80 | >50 or <80 |
| Table % | 60 to 65 | 59 to 70 | 56 to 75 | 53 to 79 | >53 or <80 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Asscher Shape | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 58 to 65 | 55 to 70 | 52 to 75 | 50 to 80 | >50 or <80 |
| Table % | 60 to 65 | 59 to 70 | 52 to 75 | 50 to 80 | >50 or <80 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
Step cuts mainly include the Emerald and Asscher cuts. They have sloping, four-sided facets that are cut below the table and run parallel to the diamond’s girdle. Their corners are generally cut, as square corners would be weaker and could cause the diamond to fracture. The advantage of step cuts is that they preserve more of the weight of the raw diamond than brilliant cuts, however they can also make inclusions and flaws appear more obvious. Because both the pavilion and crown are comparatively shallow, step cut stones are generally not as bright or fiery as brilliant cut stones, but they do accentuate a diamond’s clarity and give the diamond a less cluttered and a purer or more transparent appearance.
Because of the transparency, cut grades for step cuts are generally considered less important than for brilliant cuts.
Mixed Cuts (Cushion Cuts)
| Cushion Cut | Excellent | Very Good | Good | Fair | Poor |
|---|---|---|---|---|---|
| Depth % | 62 to 68 | 58 to 70 | 57 to 75 | 56 to 80 | >56 or <79 |
| Table % | 58 to 65 | 56 to 70 | 54 to 75 | 53 to 79 | >53 or <79 |
| Symmetry | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
| Polish | Good to excellent | Good to excellent | Good to excellent | Fair to Excellent | Poor to Excellent |
The cushion cut is the most common mixed cut, combining faceting elements from both the modified brilliant and step cuts allowing it to ensure weight preservation from the step cuts while at the same time enjoying the optical effects of brilliants. Typically the crown is fashioned like a brilliant cut and the pavilion more like a step cut. Although mixed cuts are all relatively new, dating back to the 1960s, the cushion shape is much older.
The cushion is one of the least uniform cut diamonds and comes in many different variations. In general we can separate the cut into two categories, the cushion brilliant cuts and the cushion modified brilliant cuts.
At the same time, you’ll find that cushion cut diamonds are available with a wide variety of facet structures. Suffice to say that each of these unique designs will produce a completely different look.
As a matter of fact, all of the cushion cut facet structures on the left will reflect light in different patterns. In other words, light will bounce around and reflect off the facets in accordance with the design.
In addition, the facet structure will dictate the size and intensity of the sparkle. For the most part, deciding which version of cushion cut diamond to buy is a matter of personal preference. However, you want to be sure to choose one which exhibits the highest volume of light return.
In my experience, the best option is the Brian Gavin Signature Cushion cut diamond featured at the top. Although this my be true, you might be wondering why I keep circling back around to Brian Gavin.
The fact of the matter is that I represent most of the more popular online diamond vendors. By the same token, practically all of them offer a wide variety of cushion cut diamonds with traditional facet patterns.
Be that as it may, the reality is that I know from firsthand experience that nothing compares with Brian Gavin.
Even so, you don’t have to take my word for it because I can prove it. So long as we can find a few cushion cut diamonds with the ASET and Ideal Scope images necessary to verify light performance.
There are also a number of vintage diamond cuts which remain popular as classic styles and can be described as follows.
Old Mine Cut
This is a square diamond cut with gently rounded corners and brilliant-style facets. The crown is typically high but table is small, and the culet is big enough to be visible through the top of the stone.
Old European Cut
This is a square diamond cut with gently rounded corners and brilliant-style facets. The crown is typically high but table is small, and the culet is big enough to be visible through the top of the stone.
Rose Cut
As the name suggests, this cut’s brilliant-style facets are arranged in groups that make the diamond look like an opening rose bud. The rose cut is usually made up of 12 or 24 triangular facets reaching up to form a point, a crown that rises from its base and has no pavilion. Developed prior to the use of electric lighting, rose cuts lost their popularity in the early 20th century due to their lack of brilliance.
What is an Old Mine Cut?
Old mine cut diamonds are diamonds that were cut by hand before modern cutting techniques were developed. They were typically cut during the 1800s and early 1900s and were shaped to maximize carat weight rather than brilliance and fieriness.
They have fewer facets and a more subdued sparkle compared to modern diamonds, but their unique asymmetrical shapes and romantic appeal have made them highly sought after by jewellery collectors and enthusiasts alike.
What is an Old European Cut?
An old European cut diamond is a round diamond primarily cut between 1890-1930. They were especially common during the Art Deco period. These antique diamonds were one of the predecessors to the modern round brilliant cut diamond, which is now the most popular diamond shape.
What is a Rose Cut?
A rose cut diamond is a stone that is covered with small triangular facets across its entire top (aka without a single large table facet), and typically flat on its bottom. Its faceting is meant to look like the swirling petals of a rose! Because most rose cuts do not have pavilion (bottom) facets, the give off a soft, billowy shimmer, rather than a sparkle. “Double rose” cuts are rose faceted on both top and bottom!