Diamond Shapes & Meanings
Each diamond shape has its own unique character and Rounds are no exception. When it comes to brilliance however Round diamonds outperform all other diamond shapes.
The single ‘diameter dimension’ of a round combined with a perfect ‘cone’ shape underside [pavilion] produces the most brilliant shape of all.
While much has been written about the optimal depth and table percentages for round diamonds, the conclusive study by the Gemological Institute of America [GIA] clearly indicates that maximum brilliance is produced in Round diamonds with depth and table percentages very close to 60%.
The study goes on to show minor differences in brilliance comparing depths ranging from 59.7% to 62.9% and tables from 55 to 61%. Within these parameters the difference in brilliance is difficult to detect with the naked eye however deeper stones are less valuable because of their impact on ‘face size’ relative to weight.
Round diamonds typically cost 10-15% more than fancy shapes because Rounds yield approximately 45% of the original rough weight whereas Fancy shape diamonds yield about 70%.
Why? After sawing a ‘classic’ rough diamond crystal in half, the cutter is left with two pyramid shape rough stones. In order to produce a Round diamond the 4 corners at the base of the ‘pyramid’ must be polished off resulting in greater weight loss than if the same stone were to be cut into a a different shape such as a square or cushion. Simply put, the round brilliant is by far the most popular of all the diamond shapes.
Cushion cut diamonds
Cushion cut diamonds are described in 3 ways:
‘Antique cushions’ were produced in the early 20th century during the Art-Deco era when this charming cut was the diamond of choice for the wealthy elite.
The early Antique cushion cuts tend to be deep, less brilliant and have a small table size relative to weight making those Cushions less desirable than those cut later during this period.
The best of the later examples are charming, brilliant and display an unusual brilliance caused by the larger facets unique to the Cushion cuts of this era.
‘Cushion Brilliant’ and ‘Cushion Modified Brilliant’ cuts:
Modern cushion cut diamonds are categorized as either ‘Cushion Brilliant’ or ‘Cushion Modified Brilliant.’
The GIA differentiates between these two based on specific faceting criteria, however one definition does not guarantee a more brilliant or beautiful cushion than the other.
95% of all Cushion Cuts are rejected by Adamar buyers who work diligently to identify only the best diamonds across hundreds of suppliers all around the world for their customers.
Emerald cut diamonds
Considered by many as the most elegant of all diamonds, Emerald cuts tend to be the shape of choice for those seeking larger diamonds (3.00 carats and above)
The Gemological Institute of American (GIA) describes Emerald cuts as ‘rectangular step-cuts’.
Emeralds cuts have 45 degree corners and should be beautifully layered on the underside of the diamond (pavilion) creating the illusion of infinite depth.
Emerald cuts may have different length to width ratios. One individual might respond to a rectangular shape while another might prefer more square.
While there is no one perfect length/width ratio, the most desirable Emerald cuts fall within the range 1.25:1.00 and 1.50:1.00. As the length/width ratios fall outside of this range the diamond becomes somewhat less valuable.
The most beautiful Emerald cuts have multiple steps on the underside of the stone and have clearly been cut to optimize elegance, beauty and face size.
As there are larger more window-like facets on step-cut stones such as an Emerald cut, inclusions can be more easily visible. At Adamar we are very stringent in our selection process and prefer to recommend emerald cuts that are of VS quality or above for this very reason.
Asscher cut diamonds
The GIA (Gemological Institute of America) describes Asscher cuts as “square emerald cuts” which implies a square cut with straight faceting and 45 degree corners.
Nearly 110 years ago the Asscher cut was patented by Dutch diamond cutter Joseph Asscher whose family cut the 997 carat ‘Excelsior’ diamond now part of the British Crown Jewels.
Cut correctly Asscher cuts are elegant, appear to have infinite depth and epitomize the charm of the Art-Deco era.
Too many Asscher Cuts are cut to maximize weight resulting in stones with small face size relative to weight, culets that are off center and/or corners that are too small. The most beautiful Asscher cuts have distinct corners, multiple steps, and display unmistakable charm and depth.
The clean look of an Asscher cut typically requires higher clarity grades since even a small [VS+] inclusion might be visible to the eye. In rare instances an exceptional SI1 clarity might be invisible to the naked eye making these Asscher Cuts less costly and a ‘buyer’s best friend’.
Princess cut diamonds
Princess cut diamonds are square, brilliant cuts with pointed corners.
Princess cuts are slightly less costly than equivalent round diamonds because square diamonds yield about 75% from an original rough stone whereas rounds yield +-45%.
As with all diamonds, cutters tend to leave unnecessary weight on Princess cuts in the girdle, crown and pavilion in order to maximize weight. Be sure your Princess cut has the correct, ‘face size’ relative to weight.
The ideal length to width ratio for a Princess cut should be close to square with a ratio no greater than 1.05 : 1.00.
Depth and table percentages for Princess cuts should fall between 70 and 75% and buyers should take particular note that the culet on Princess cuts is centered perfectly to ensure even brilliance all the way to the edges and avoid ‘windows’ that distract from the beauty and value of the stone.
Radiant cut diamonds
Radiant cut diamonds are described by the Gemological Institute of America [GIA] as ‘Cut Cornered Modified Brilliants’.
Radiant cuts are similar to princess cuts however have 45 degree corners with a slightly different faceting pattern and personality.
Set in jewelry Radiant and Cushion cuts are often similar and the technical differences noted only under close examination. Radiant cuts may vary in shape from rectangular to square and cut beautifully both are valid choices based on individual preference.
There is no ‘ideal’ depth and table parameters for fancy cut diamonds [other than rounds] since these percentages will vary based upon the unique length, width and depth measurements of each stone. Radiant cut diamonds are known to bring out deeper colours than some other cuts, and as such are a popular cut choice to maximize the colour in fancy coloured diamonds.
Pear shape diamonds
Possibly the most demanding of all shapes to produce, a truly magnificent Pear shape somehow ‘speaks to you’ the minute you set eyes on it.
Proportion in a Pear shape is top priority; length to width ratio should fall within the range 1.50:1.00 and 1.65:1.00 with shorter or longer proportion resulting in a diamond that is less elegant and valuable.
In addition face dimensions, a gorgeous Pear shape must have the depth to support these dimensions to ensure consistent, even brilliance all the way to the edges and minimize any ‘bow-tie’ effect in the heart of the stone.
Identifying only the most beautiful Pear shapes demands rejecting more than 95% of those produced. We at Adamar do precisely this as we acquire only the absolute best Pear shapes from around the world for our inventory.
Oval shape diamonds
Oval diamonds are described by the GIA as ‘Oval brilliant’.
Cut with skill and care Oval diamonds should provide a larger ‘face to weight ratio’ than most other shapes making this cut particularly attractive to many.
With financial incentive to produce heavier diamonds, Ovals are rarely cut beautifully; Most have inappropriate length/width to depth ratios and are either too shallow, too deep, or not true Ovals.
At Adamar, we reject 95% of all Oval diamonds produced in order to identify only the absolute best Oval diamond shapes from around the world for our customers.
Defining a specific depth and table percentage range for any fancy shape diamond is not realistic. Specific ‘depth and table percentages’ are a reliable metric only when related to either round or perfectly square diamonds that have a single face dimension.
Marquise shape diamonds
The Marquise shape was named in the 1700’s after Marquise de Pompadour of France. The elongated shape of a Marquise cut creates the illusion of a diamonds larger than its actual weight and for many decades this cut was the most sought after of all fancy shapes.
As with all Fancy shape diamonds the Marquise must be cut with exceptional symmetry and proportion in order to produce a diamond with even brilliance to the edges and a minimal ‘bow-tie’ through the heart of the stone
The ideal length to width ratio for a Marquise cut is 2.00:1.00 and stones with proportion more than 10% outside of this ratio are less desirable and valuable.
A Marquise cut must have the appropriate depth to support the outer dimensions; If too shallow the diamond will appear glassy and if too deep, the weight to ‘face size’ ratio will cause the stone to appear small.
While a Marquise cut diamond is not for everyone when cut correctly this shape is beautiful, brilliant and can provide a generous big look.