Diamond Shape

Did you know that the 10 universally recognized diamond shapes that we know today are in fact relatively recent innovations, created and given a theoretic, public platform beginning only in the early 20th century? The 14th century marked the start of European diamond cutting novelties that yielded shapes which, while being the predecessors of today’s cuts, are unknown to the modern day diamond consumer: The Point Cut, Old Eight Cut, Pendeloque, Briolette, Rosette, Mazarin and Peruzzi. These advances were in fact the stepping stones to today’s 10 contemporary diamond cuts, the global diamond industry’s accepted standards.

We invite you to look, learn, and marvel. And if you have any questions about diamond shapes,Jagan Jewellers welcomes you to Contact our Diamond Experts.


The round brilliant diamond is the most popular and perhaps the most technically advanced of all of the diamond shapes. Only after the development of new diamond cutting technology and a breakthrough in research regarding proportion and symmetry, was the round brilliant born. The round brilliant that we know today was invented by Marcel Tolkowsky, a Belgian mathematician born to a family of diamond cutters who, in 1919, wrote his doctoral thesis on diamond proportion and symmetry, and “invented” the round brilliant. According to his research, the round brilliant, with its 58 facets, has the perfect proportions and symmetry to maximize a diamond’s brilliance and fire. This superior quality, therefore, allows for those interested in the round brilliant to be quite flexible regarding the other qualities of their diamond: color, cut and clarity.



The princess diamond is the most popular shape after the round brilliant and is typically square in shape, although it can also be rectangular. The princess shape was created in the 1980s and displays the same high degree of brilliance as the round brilliant. It is a unique and distinctive alternative to the popular round brilliant. It’s important to note that when weighing color grades and prices, sometimes a lower color grade diamond in a princess shape will manifest as visible color in the corners of the stone.

What is the ideal cut for a princess diamond?

Princess cut diamonds are the second most popular diamond for engagement rings after round brilliant diamonds, and are valued because of their terrific value and appearance.

So, how does one determine the ideal cut proportions for a princess diamond? Like with round brilliant diamonds, the ideal cut for a princess diamond is determined by many factors, most importantly depth and table proportions as well as crown and pavilion angles. The cut is also determined by the symmetrical arrangement of the facets on the diamond, which is simply put, how well all of the facets align with each other in a way that maximizes brilliance and fire.

So what are the ideal proportions of a princess cut diamond? It is Jagan Jewellers’ recommendation that for a princess diamond to have ideal proportions, its table must be within 62-68%, the depth must be 64-75% and the crown height should be 10-15%. The symmetry should also be very good to excellent.

Also, another important thing when determining the ideal cut for a princess diamond, it is crucial to take the width to length ratio into account, because this will decide how rectangular or square the diamond is. The ratio is calculated by dividing the length against the width. A perfect square princess diamond will have a ratio of 1, while a more rectangular one will be over 1.05.



The emerald cut is not a brilliant cut, but rather features a large open table with step cuts. The emerald cut is traditionally rectangular and most closely resembles the natural diamond shape. Although the emerald diamond is not as brilliant as the round shape or princess shape, it is considered to be an elegant cut, vintage in style, and less “flashy” than other shapes.

Note that due to the large table of the emerald shape, inclusions and color can be easier to detect. It is recommended that you choose a diamond with a higher clarity and color grade than you would if choosing a brilliant diamond.


The Asscher diamond is almost indistinguishable from the emerald cut aside from its larger step facets, dramatically cut corners and square shape. Also, because of its proportions, it typically has more light reflection and fire than an emerald shaped diamond. As with the emerald diamond, the Asscher diamond also has a certain antique, elegant air about it. The Asscher diamond, similar to the princess diamond, can sometimes show color impurities in its corners. Therefore, although the price for an Asscher diamond with lower color grade can be enticing, we recommend choosing one with an H color grade or higher.


The oval diamond is a modified round brilliant shape. While this means that it has a high level of brilliance, if the stone is not a premium cut, there is a greater likelihood of the bowtie effect, or a dark strip that appears in the center of the stone in the shape of a bowtie. GRT Jewellers carries only quality cut oval diamonds with optimally cut angles.


The shape of the marquise diamond was allegedly inspired by the mouth of the beautiful Marquise de Pompadour. It has a football-like shape that comes to a point on either end, which is said to maximize the illusion of increased diamond weight, giving the appearance of a much larger-looking diamond. A modification of the round brilliant, the marquise shape also offers a high level or brilliance and light reflection, and due to its long, lean frame, marquise diamonds are frequently set with side stones.


The radiant shape was the first diamond of rectangular shape to have a brilliant facet pattern used both for the crown and pavilion, offering a brighter and more brilliant stone than the emerald shape. The radiant shape was born over decades ago and is considered to be the father of ‘fancy cut’ diamonds. The proportioning, facet arrangement and shape of the radiant diamond is considered a good shape for colored diamonds since it is widely held that these factors intensify color.


The heart shaped diamond is a modified brilliant diamond shape and can vary greatly in length and width. The heart shape, with its classic connotation of romance and love, is a popular choice for anniversary rings and Mother’s Day necklaces. GRT Jewellers recommends that when shopping for a heart shaped diamond you should look for a stone that is perfectly symmetrical: Where the top arches of the heart are even in height and width so that its overall shape is aesthetically pleasing. The cleft in any well-cut heart shaped diamond should be sharp and definite. Also, the heart shaped diamond, similar to the princess shape, can sometimes show color impurities at its corners. Therefore, although the price for a heart shaped diamond with lower color grade can seem inviting, we recommend choosing a heart shaped diamond with an H color grade or higher.


The pear shaped diamond is also a modified brilliant shape, a combination of the round and marquis shapes. It is also known as a teardrop shape for its round bottom and sides which taper to one common point. Some of the world’s most famous and most highly graded diamonds have been cut into the pear shape. An elongated pear shape is also considered a specifically flattering shape when worn mounted on a ring with the point facing upwards towards the nail, thus creating an apparent slimming effect of the finger.


The cushion shaped diam ond is technically known as the Old Mine Cut, a shape born before the 1900s. It developed its name due to its similarity to the shape of a pillow and is therefore also known as the “pillow cut”. The cushion shaped diamond was one of the most popular diamond shapes before the invention of the round brilliant. Once the round brilliant was developed, the brilliant angles and proportions were incorporated into the cushion shape. The cushion shape has rounded corners and now features larger facets, which increase the brilliance of the stone. It should also be noted that the cushion shape is a popular choice for fancy colored diamonds since the color is displayed evenly throughout cushion shaped diamonds. It should be noted that the large facets of a cushion diamond can make it easier to detect inclusions in the

stone. It is therefore recommended that those in the market for a cushion diamond choose a color grade of I or greater and a clarity grade of S1 or higher.



Diamond cut refers to the proportions, polish, and symmetry of a stone: the three main factors involved in creating a diamond with optimal light reflection. Good light performance, the term used to describe light refraction and light return through the top of the diamond, is what many refer to as the “brilliance” of a diamond.

An excellent diamond cut produces a diamond with a high light return, dazzling brilliance, fire and scintillation. A poor cut, on the other hand, can cause light to seep out of the sides and bottom of the diamond or it can limit the amount of light that enters a diamond. Poor cuts can therefore cause the diamond to appear dark, dull and lifeless, despite its color and clarity grades. This fact makes a diamond’s cut the most significant factor to influence appearance. For this reason, GRT Jewellers suggests that you choose the diamond with the highest cut grade that falls within your budget.

The cut of a diamond influences three main qualities:


Brilliance is the total amount of light reflected by a diamond. When light hits the diamond’s surface, some light enters and some is reflected back. The most immediate light reflected back is returned by the crown’s angles.


Scintillation refers to the flashes of light, or sparkles, which are produced when a diamond is tilted from side to side. The light that isn’t immediately reflected back enters the diamond and reflects from the inside walls toward the center of the diamond. This light, which bounces off the internal walls of the diamond, is the quality described as scintillation.


A diamond’s fire refers to the dispersion of light into different colored light. Once the light is bounced off the inside walls towards the center of the diamond, it then shoots back through the top of the diamond. Because the light is slightly bent by the diamond, a color spectrum is visible when light exits the top of the diamond.

Understanding Diamond Anatomy

To properly understand a diamond’s cut, it is important to understand the terminology of basic diamond structure as it relates to proportion, symmetry and polish.

Diameter: The diameter is the width of a polished diamond from one side of the girdle to another

Table: The table is the largest polished facet of the diamond on the top face of the stone

Crown: The crown is the top part of the diamond that is measured from the surface of the table to the girdle

Girdle: The girdle is the widest edge of the diamond where the crown ends and meets the pavilion

Pavilion: The pavilion is the bottom part of the diamond that begins at the girdle and extends downward to the point of the culet

Culet: The culet is the tiny flat facet at the bottom tip of the diamond

Depth: The depth of a diamond refers to the total length of a diamond, measured from the culet to the table

Proportion, Symmetry and Polish

Diamond Proportion

To optimally capture light and reflect it back, a diamond’s pavilion must have accurate angles and depth. If the angle of the pavilion is too shallow or too deep, light will escape or leak out, creating dark and dull “stains.” The crown angle is also extremely important since this affects the way that light enters and exits the diamond.

Not only are the angles important, but depth percentage and table percentage are also key factors that contribute to the quality of a diamond’s cut. Depth percentage refers to the depth of the diamond divided by its diameter. Shallower diamonds have low depth percentages whereas deeper diamonds have higher depth percentages. A good target depth percentage for a round diamond is considered to fall between 59 and 62.5%. Table percentage refers to the width of the table divided by the diameter. Again, diamonds with a higher table percentage have larger tables, and diamonds with a smaller table percentage have smaller tables. A good target depth percentage for a round diamond is considered to fall between 53 and 59%.

Diamond Symmetry

A diamond’s facets must be symmetrical in order to maximize the amount of light that enters and exits the stone. Diamonds with poor symmetry look slightly distorted, unbalanced and improperly shaped. Moreover, they will affect brilliance, scintillation and fire. Many asymmetrical round stones are not completely round, or have misshapen facets or off-center culets. GRT Jewellers recommends that you consider round brilliant diamonds with a symmetry grade no lower than Very Good, and fancy cut diamonds with a symmetry grade no lower than Good.

Diamond Polish

Once a diamond is cut, each facet of the diamond is polished. If the polishing is done improperly, it can leave scratches and streaks that are similar to the marks left behind after a car waxing. An Excellent diamond polish is a diamond which has very few or no scratches.GRT Jewellers recommends that you consider diamonds with a polish grade no lower than Good.

Cut Grades

Ideal/ Excellent – Excellent light performance. Reflects almost all of the light that enters. Rare and extremely beautiful cuts.

Very Good – Very good light performance. Reflects almost all of the light that enters. Very Good diamond cuts are considered to be an outstanding value.

Good – Good light performance. Reflects most of the light that enters. Good diamond cuts are far less pricey than Very Good cuts.

Fair – Not as brilliant as a Good cuts or above, Fair diamond cuts are still considered good quality diamonds.

Poor – Poor cut diamonds are typically cut too shallow or too deep causing much of the light to leak out of the diamond’s sides and base. Most high end diamond retailers do not carry Poor cut diamonds.