By Gary A.
Edited by Brian M.
Published Jul 29, 2022
Edited on Dec 18, 2024
When it comes to maximizing sparkle, understanding diamond depth and table proportions plays a key role in ensuring your stone shines as brilliantly as possible.
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By now, you likely already know how the Four Cs affect a diamondâs appearance. Namely, how cut impacts sparkle more than any other factor â and, for that reason alone, how important it is to get it right. But what does âgetting it rightâ even mean? For most of us, cut is easily confused with shape â a decision that comes down to personal preference, rather than anything objective or measurable.
Still, as one of the Four Cs, cut is every bit as important as the rest â and, in arguably, more important than any other for those looking to ensure that light will dance across the surface of your ring in a fantastic display of brilliance and fire.
There are multiple factors influencing the strength of a diamondâs cut, from the surface to the mirror-like depths of the stone.
The table and depth of a diamond are two separate factors, although they both strongly influence the quality of a diamondâs cut.
The table refers to the uppermost portion of the diamond, while, as the name suggests, a diamondâs depth refers to a very precise measurement made from the table to the culet â or, in other words, its lowest point.
The value of an excellent diamond cut is far greater than the sum of its parts, but it helps to know exactly what these parts are before you make a decision. When you break, say, a Round cut diamondâs cut down, you get the culet, the pavilion, the girdle, the crown and, of course, the table. This table plays a prominent role in sparkle, which means that it pays to know your stuffâ¦
This is the flat surface at the very top of the diamond. From Round cuts to Emerald, the table will look a little different on every diamond shape, though it plays the same vital role regardless.
More specifically, the table is the largest facet the diamond features â although the precise size of the table varies. Even in diamonds of the same shape, the table size will differ significantly â a factor which will directly impact the quality of the stoneâs cut.
Why? Because the table needs to let light into the diamond, while also refracting it into other areas. To accomplish both of these tasks, it must represent a pretty specific percentage of the diamondâs surface area â not an easy task, even for the most skilled of diamond cutters.
The table is an intrinsic part of any diamond. Its job is to allow light into the diamond, to disperse it between the diamondâs many facets, and to reflect it back from the pavilion and out the top of the diamond as brilliance and fire.
If youâre feeling like the diamond table is playing two totally different roles, youâd be right. Itâs got to let in light, but also refract light onto the crown, rather than letting it straight back out the table. Itâs got to be small enough to do that, but not so small that the diamond looks dull and sparkly.
As a result, getting the proportions of the diamond table right is absolutely vital to creating a good diamond â and itâs not easy. Thankfully, your job is a lot easier and simply involves getting to know the âidealâ diamond table and depth â and knowing the trouble that can be caused by one that is out of proportion, even if itâs just a small amount.
The amount of light able to enter the diamond will be reduced, meaning that the diamond will not be able to sparkle as much as it otherwise could, even if it has been given excellent grades for clarity and color.
The beautiful sparkle diamonds are capable of creating depends on the complex pathway light takes through the many facets cut into the surface, and the fascinating internal structure. Of course, it also depends on the diamondâs ability to draw in light in the first place, since diamonds do not âcreate itâ for themselves.
As we mentioned before, the table is the largest facet a diamond has. It sits on the most prominent part of the diamond and, particularly when it has been set within a ring, will be responsible for drawing in most of the light that travels through the stoneâs center.
So, an undersized table will fall short of doing its most important job properly and will limit the amount of light the diamond can transform into sparkle.
As we mentioned above, the diamondâs table needs to play two roles at once â roles that, for the most part, stand in opposition to one another. If the table comprises too much of the diamondâs upper surface, there will be noticeably less sparkle. Then again, if it comprises too little, the same issue will occur.
In order to be considered ideal, diamond tables need to be above a certain percentage, but below another. This can seem a little confusing until you get to know the ideal ârangeâ for your chosen diamond shape, and why itâs better to use percentages in the first place.
Table percentage refers to the ratio that exists between the widest point of the diamond, and the width of the table. When it comes to grading a diamondâs cut, a certain percentage range has to be met in order for the diamond to be considered Excellent.
There is no universally ideal measurement for the table. Itâs impossible to say that, say, a table with a measurement of 6mm is the best since this measurement would overwhelm some smaller diamonds, and look far too small on others. So, even if a diamondâs 6mm table turns out to be the perfect size for maximizing sparkle, it will be poor enough to take thousands of dollars off another diamondâs value.
This is why we are given table percentages, since an optimal percentage range will be pretty much the same whether youâre looking at a one carat diamond or a ten carat diamond (provided, of course, that theyâre the same cut.
For the traditional Round cut diamond, a table of between 56% and 59.9% is considered Excellent, while anything below 49.9 is Poor. Other cuts differ somewhat â and, in many cases, offer a little more leeway than the Round diamond when it comes to table percentage.
For instance, the ideal table percentage for square diamonds is much broader. The Radiant cut features an âExcellentâ table percentage of between 61% and 69.9%, while the Asscher offers a range of 60% to 65.9%.
Below, weâve included a table of âExcellentâ and âVery Goodâ table percentages for all of the most popular diamond shapes.
Shape | âExcellentâ Table % Range | âVery Goodâ Table % Range |
Asscher | 60% â 65.9% | 58% â 59.9%or66% â 69.9% |
Cushion (Square and Rectangle) | 60% â 65.9% | 58% â 59.9%or66% â 69.9% |
Emerald | 60% â 65.9% | 58% â 59.9%or66% â 72.9% |
Marquise | 53% â 65.9% | 52% â 52.9%or63% â 65.9% |
Oval | 55% â 62.9% | 52% â 54.9%or63% â 65.9% |
Pear | 53% â 62.9% | 52% â 52.9%or63% â 65.9% |
Princess | 67% â 72.9% | 60% â 66.9%or73% â 75.9% |
Radiant (Square) | 61% â 69.9% | 57% â 60.9%or70% â 72.9% |
Radiant (Rectangle) | 60% â 66.9% | 58% â 59.9%or67% â 70.9% |
Round | 56% â 59.9% | 54% â 55.9%or60% â 60.9% |
For anyone looking to buy a beautiful ring, of any size or shape, to set within an engagement ring (or any jewelry, for that matter), it is never advisable to go below an Excellent or Very Good cut grade.
Diamonds featuring a table that exceeds the shapeâs ideal percentage range will have limited fire, while those that feature a table that falls below the shapeâs ideal percentage range will fail to impress with their sparkle.
While a good size of table is vital to a diamondâs ability to produce plenty of fire and brilliance, thatâs not the only factor diamond cutters, jewelers or, for that matter, you need to consider in order to get the best possible diamond for your money.
Put simply, depth refers to the distance from the diamondâs table to its lowest point. Like the table, depth is most commonly conveyed as a percentage, rather than a measurement.
Why? Because, just as before, there is no ideal measurement for depth â although there is an ideal ratio or percentage.
This percentage is reached by dividing the height of the diamond by the width, and will once again determine whether it is Excellent, Very Good, Good, Fair or Poor. Again, you want to aim for Excellent or Very Good or risk a diamond with impaired light performance.
When we think of diamonds â and, more specifically, diamond engagement rings â it is much more common for us to picture that birdâs eye view. We imagine ourselves looking down on the table and crown of the diamond since when it is worn on the finger, this is the part that will be most prominent.
It is important to remember, however, that every part of the diamond influences that light performance you see dancing across the surface. In other words, a beautiful sparkle is only made possible by an all-round beautiful diamond.
A diamond with less-than-ideal proportions will have a dulled sparkle, due to the fact that light is being refracted and lost through the pavilion (the bottom portion of the diamond), rather than the table.
This is similar to what happens when a diamond is cut too shallow. While the path light takes through a deep cut diamond will be totally different to the path light takes through a shallow cut diamond, the end result is pretty much the same â and just as undesirable in either case.
If light is lost through the pavilion rather than the table, then that all-important birdâs eye view will be what suffers the most. Looking down on the diamond, you will see less sparkle, and a diamond lacking the liveliness and shine of better proportioned stones, even if they feature the same shape and carat weight.
There is no definitive answer to this question, although, as with the table percentage, there is an ideal depth percentage range into which any good diamond will fall.
The diamonds used in the center settings of engagement rings differ drastically in size, from below one carat to well over twenty â although not all of us can carry off Beyoncéâs 24 carat Emerald cut diamond. What this means is that there is no ârecommended depth measurementâ out there that could apply to all diamonds, despite the fact that countless beautiful diamonds are cut and graded each year.
Similarly, no single measurement (or percentage) could apply to all of the diamond shapes out there, since each one boasts different proportions and varying numbers of facets.
So, just as before, here are the ideal diamond table and depth ranges for each shape.
Shape | âExcellentâ Depth % Range | âVery Goodâ Depth % Range |
Asscher | 63% â 67.9% | 58% â 62.9%or68% â 69.9% |
Cushion (Square and Rectangle) | 63 â 67.9 | 58% â 62.9%or68% â 69.9% |
Emerald | 63% â 67.9% | 59% â 62.9%or68% â 69.9% |
Marquise | 58% â 62.9% | 56% â 57.9%or63% â 65.9% |
Oval | 58% â 62.9% | 56% â 57.9%or63% â 65.9% |
Pear | 67% â 72.9% | 64% â 66.9%or73% â 74.9% |
Princess | 67% â 72.9% | 64% â 66.9%or73% â 74.9% |
Radiant (Square) | 61% â 67.9% | 59% â 60.9 %or68% â 69.9% |
Radiant (Rectangle) | 63% â 67.9% | 59% â 62.9 %or68% â 69.9% |
Round | 59% â 62.3% | 58% â 58.9%or62.4% â 63.5% |
Diamond depth and table are two of the most significant factors behind the quality of the diamondâs cut, and, as a result, its sparkle.
Cut is crucial â itâs the deciding factor behind whether or not a diamond is worth your time or not. And, while cut comprises far more features than just depth and table, there really is no room for error when it comes to these two percentages.
Itâs easy enough to tell yourself that a deep or shallow diamond wonât look too deep or too shallow once it is set within the ring, or that a smaller table adds to the unique âcharmâ of the diamond, but thatâs why itâs so important to understand how these two features will impact the stoneâs light performance, and why you should never compromise on that.
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