Diamond's Cut

What Is The Cut Of A Diamond?

Have you ever noticed how many surfaces a diamond has? A diamond’s cut refers to how well-proportioned the dimensions of a diamond are, and how these surfaces, or facets, are positioned to create sparkle and brilliance. For example, what is the ratio of the diamond’s diameter in comparison to its depth? These small, yet essential, factors determine the diamond’s beauty and price.

THERE ARE THREE DIFFERENT CUTS: 

The diamond cut grade chart also includes an Ideal grade. Cut quality is graded by the as AGS Ideal, Excellent, Very Good, Good, Fair or Poor. When looking at diamonds, we recommend only considering Ideal cut diamonds for the best quality.

IDEAL CUT: This rare cut represents roughly the top 3% of diamond cut quality. It          reflects most of the light that enters the diamond.

VERY GOOD: This cut represents roughly the top 15% of diamond cut quality. It reflects nearly as much light as the ideal cut, but for a lower price.

GOOD: This cut represents roughly the top 25% of diamond cut quality. It reflects most of the light that enters, but not as much as a Very Good cut grade.

Excellent	Excellent Cut Diamonds provide the highest level of fire and brilliance. Because almost all of the incoming light is reflected through the table, the diamond radiates with magnificent sparkle.
Very Good	Very Good Cut Diamonds offer exceptional brilliance and fire. A large majority of the entering light reflects through the diamond’s table. To the naked eye, Very Good diamonds provide similar sparkle to those of Excellent grade.
Good	Good Cut Diamonds showcase brilliance and sparkle, with much of the light reflecting through the table to the viewer’s eye. These diamonds provide beauty at a lower price point.
Fair	Fair Cut Diamonds offer little brilliance, as light easily exits through the bottom and sides of the diamond. Diamonds of a Fair Cut may be a satisfactory choice for smaller carats and those acting as side stones.
Poor	Poor Cut Diamonds yield nearly no sparkle, brilliance or fire. Entering light escapes from the sides and bottom of the diamond.

Diamond cut prices are based on the precision and quality of the cut—primarily its proportions and symmetry-the depth, table and all other proportions are as exact as can be.

If the facets (the glossy flat surfaces of a diamond) are proportional, for instance, they refract and reflect light back to the eye in tremendous fashion.Diamonds that aren’t as precisely cut have facets and pavilions that do not refract and reflect light as spectacularly.

The amount of light return and brilliance found in an exceptionally cut diamond. Without brilliance and fire, a diamond is less than radiant—no matter the Carat Weight or table size.

DIAMOND PROPORTIONS:

To further understand the factors impacting Diamond Cut quality, let’s examine a diamond’s proportions, primarily its table, width and depth. These elements are universally measured and are excellent indicators of a diamond’s cut quality.

Diamond Cut Proportions directly affect a diamond’s ability to reflect light and provide brilliance. Proportions are based on the ratios between size, angle and shape of each diamond facet. Various combinations of these elements impact how the diamond will interact with light, which determines its overall beauty and lasting appeal (as well as its GIA grading).

Here are the main factors that affect the price of a diamond:

• Proportions (table, width, depth)

• Symmetrical facets (the mirrors, windows and steps of a diamond)

• Brilliance (brightness of white light reflection)

• Fire (dispersion of colored light)

• Scintillation (the flashes of sparkle when light moves)

• Finishing details (permanent treatment and polishing)

About Diamond Table:

Diamond table % is determined by dividing the width of the table (top surface area) by the width (diameter) of the diamond. For example, if the table facet is 3.5mm wide, and the diamond is 5mm wide, the table % is 70%.

If the table percentage is too large, light won’t reflect off of the diamond’s crown angles and facets. Vibrant reflections of color won’t be seen as the light will escape from the top of the diamond instead of reaching the eye.

If the table percentage is too low,light will remain trapped inside the diamond and be emitted through other parts of the diamond instead of to the eye.The Ideal table % depends heavily on the diamond shape.

About Diamond Depth:

Depth % refers to the height of the diamond, from the culet to the top of the table. Depth is measured in millimeters and percentage. By dividing the depth by the width, the depth % is achieved.

As an example, if a diamond is 4mm in depth and 4.5 mm in width, the depth percentage is 88.8%.

In most cases, a lower depth % of two equal carat diamonds will appear larger due to the increased width. On the other hand, a depth % that is too low can create a darker appearance as it will not reflect light as powerfully.

What happens when a Diamond Cut is too shallow?

When a Diamond Cut is too shallow, light hits the pavillion at a low angle. The light travels through the diamond and exits through the sides, instead of reflecting through the table and to your eyes.

While shallow cut diamonds may seem large based on their table size (they are also called Spready Diamonds), the escape of light at the bottom significantly reduces the diamond’s brilliance, sparkle and fire.

What happens when a Diamond Cut is too deep?

When a diamond is cut too deep, light hits the pavilion at a sharper angle, causing it to immediately reflect to another pavilion. The light is forced to retract and pass through the bottom of the diamond. As this happens, light is dulled and the diamond becomes less vibrant and radiant.

A Diamond Cut that is too deep also tends to look smaller than those of an ideal cut.

What is the best cut for a Diamond?

Simply put, a well cut diamond maximizes the light that strikes each pavilion. Instead of escaping through other parts of the diamond, light reflects back through the crown and table.

When it comes to determining the highest grade possible, GIA uses the term “excellent” or “ideal” cut. These cuts are well proportioned with optimal facet angles, allowing the brilliance and fire to pass through the table for all to see.