How a Diamond’s Cut Affects Price

If you have tried checking out diamonds to buy, you have probably heard about the 4Cs of these gemstones – cut, carat, clarity, and color. These four characteristics of diamonds have a direct effect on the price and market value of the stone, and the cut is one of the most significant factors that can affect the price. The better the diamond cut is, the more beautiful it looks – the higher the price.

What is a diamond “cut”?

To understand pricing better, you have to be familiar with what a diamond cut is. Cut refers to how well-proportioned a diamond is, and it refers to the precision of the facets, polish, and symmetry of the diamond. A slight modification of the angle between the two facets can change the path of the light through the crystal, which affects its brilliance and clarity.

Here are the factors that affect the quality of cut, which also impacts the value, price, sparkle, and aesthetic appeal of the diamond:

  • Proportions (width, table, and depth)
  • Symmetry (mirrors, windows, steps, and windows of a diamond)
  • Brilliance (brightness of the white light reflection)
  • Scintillation (flashes of sparkle when light moves)
  • Fire (dispersion of colored light)
  • Finishing details (polishing and permanent treatment)

When you’re looking to see how well-cut a diamond is, check how its angles and facets reflect light. Note how sparkly and bright the light return is when the diamond is placed under a normal lamp. Gauge the diamond’s fire and brilliance, and make sure to look for any dark spots within the gemstone.

A poorly cut diamond will not reflect well back to the eyes, making it look dull and lifeless.

Diamond cut proportions

To better understand what a diamond cut is, let’s examine diamond proportions.

1. Diamond table

The diamond table is the flat facet located on the top of the stone when the diamond is face up. It’s also the largest facet on a diamond that plays a vital role in the brilliance of the stone.

Diamond tables are measured in percentages. It is determined by dividing the width of the table by the diameter of the diamond. For instance, if the table facet is 3mm wide and the diamond is 5mm wide, the table percentage is 60%.

The ideal table percentage heavily depends on the diamond shape. For a round diamond, anything between 50 to 69% is considered alright. At this proportion, the table is large enough to let light enter the stone at correct angles to retract and refract off the smaller facets below.

If the table percentage is too high, the light won’t reflect off the diamond’s facets and crown angles. Color reflections won’t be seen as the light will escape and be emitted to the other parts of the diamond instead of reaching the eye of the observer. Meanwhile, if the table percentage is too low, the light will remain trapped inside the diamond.

2. Diamond width

The diamond width of a diamond is measured from one end of the girdle to the other end of the girdle, where the diameter of the diamond is at its widest point. It plays an important role when it comes to determining the length to width ratio that signifies how proportionate the diamond will be along with its intended shape.

3. Diamond depth

Depth is an important feature of a diamond, for both cut quality and for making a modest diamond appear bigger. Diamond depth is the height of the diamond from the culet to the table of the diamond. When describing the depth, it’s also discussed in percentages like the table. To determine the depth percentage, divide the depth of a diamond to the measurement of the width. For instance, if the diamond is 3.5 mm in depth and 4.5 mm in width, the depth percentage is 77.78%.

In most cases, a diamond with a lower depth percentage of equal carat will appear larger due to increased width. A depth percentage that is too low makes a darker-looking diamond as it will not reflect light as powerfully.

The proportions of a diamond cut directly affect a diamond’s ability to provide brilliance and reflect light. When a diamond has a shallow cut, light hits the pavilion (lower half of a diamond) at a low angle. Because of this, the light travels through the diamond and exits through the sides instead of reflecting through the table. On the other hand, if the diamond cut is too deep, the light hits the pavilion at a sharper angle, which makes it reflect another pavilion. This way, the light is forced to pass through the bottom of the diamond. This makes the diamond dull and less vibrant.

A well-cut diamond maximizes the light that strikes each pavilion, making it reflect back through the table, so it looks sparkly and shiny.

GIA diamond cut grades

When it comes to checking out the highest cut grade possible, the GIA (Gemological Institute of America) is one of the most renowned and well-respected diamond grading entity. As an independent entity, the GIA doesn’t have a financial part in the sale of the diamond. So when you are looking for a diamond to buy, it’s advisable to seek a GIA certificate to view the cut grade of the diamond.

Here’s how they categorize the diamond cut grades:

  • Excellent – These kinds of diamonds provide the highest level of brilliance and fire. Since almost all incoming light is reflected back through the table, the diamond radiates with a sparkle. Diamonds with excellent cut add to the higher price.
  • Very good – These diamonds feature exceptional brilliance and sparkle, with much of the light reflecting back through the table. To an ordinary observer, they provide the same sparkle as the excellent grade.
  • Good – These diamonds offer sparkle and brilliance, as much of the light reflects back through the table to the eye of the viewer. They provide beautiful diamonds at a lower price.
  • Fair – These diamonds have little brilliance as light exits easily through the bottom and sides of the diamond. Fair cut diamonds can be a fine choice for diamonds with smaller carats and those that act as side stones.
  • Poor – These diamonds yield very little to no sparkle, fire, or brilliance. The light escapes from the sides and bottom of the diamond. Reputable jewelers usually do not sell this kind of diamond cut grade for their engagement rings.

How cut quality affects the price

When it comes to diamonds, size truly matters, but it isn’t the only thing that can assess the quality and the value of the gemstone. Diamond pricing is actually a complex mechanism that considers a lot of different factors.

In general, a diamond with a better quality cut has a higher price than diamonds of the same with a lesser grade. This is simply because more rough material has to be removed to achieve a better cut. Making a diamond symmetric, proportional, and polished means there’s a higher wastage of the raw stone. If you have two similar raw stones – one bigger but with a poor cut, and a smaller one but with an excellent cut, obviously the smaller one will be worth more value despite its lesser carat weight. When more rough material is removed, the loss of carat weight by improving cut quality needs to be compensated at a higher price.

On top of that, additional costs are paid for skilled labor and additional hours required to polish an ideal cut diamond, as compared to a poor cut diamond. Also, it is not always feasible to create a high-quality cut for every piece of diamond because it’s not profitable to do so. This is why you can find sub-par diamonds cut only for retaining carat weight and not for beauty.


The amount of brilliance found in an exceptionally cut diamond is worth the extra cost. If a diamond has no brilliance and fire, a diamond becomes less radiant and less aesthetically pleasing, no matter the carat weight or table size is. Avoid compromising on the cut grade if you want to buy the best for your money.

Spending more for a better cut than getting a better color grade or clarity grade will have an impact on the beauty of your diamond. Clarity grade, for instance, doesn’t has to be the best of all to make your diamond look gorgeous. If the inclusions aren’t in the right position, then it obstructs the path of light that exits the diamond through its table, the stone can look perfect even in less clarity. Similarly, buying a lower carat diamond is a better choice than buying a lower cut grade. This is a wiser compromise for you to get the best-looking diamond that your budget can afford.