Diamond Learning Center - Diamond Cut

Diamond Cut Tutorial

Many people (and even some experts) confuse the diamonds cut is and the diamonds shape. A diamond cutter takes a raw diamond and polishes the diamond into a predetermined shape. The diamonds shape is the determined design of the diamond such as round brilliant, princess, emerald, radiant, cushion, marquise or pear shape. A diamonds cut is a measure of the diamond's reflective properties not the shape.

The diamonds cut is the most important of the four Cs value factors. The diamond cut quality affects the reflection and scintillation properties and values of a diamond. A good cut gives a diamond its brilliance and diamond fire which is that brightness that seems to come magically from the diamond. The quality of the cut are determined by two factors. The quality of the diamond facets polishing and the geometry of the diamond. The angles and finish of any diamond are what determine the diamonds ability to handle light which leads to brilliance, scintillation and fire.

Premium Ideal Cut Diamonds

Premium or ideal cut diamonds are extremely well-cut diamonds. It is unmistakable when you see a ideal cut diamond. Light enters through the table of the diamond and travels to the pavilion where it reflects from one side of the diamond to the other before reflecting back out of the diamond through the table. The light exiting the diamonds table is reflected directly into the viewing eye. As can be seen in the ideal cut diamond image on the left, the diamond has no light leaking out of the bottom of the diamond. Even a small amount of light in a room will have an amazing visual effect on this ideal cut diamond. This light is the brilliance and scintillation. The flashing and fire ofideal cut diamonds makes diamonds so incredible.

There are varying cut standards which determine if a diamond is a premium or ideal cut. Diamond grading labs have determined different standards. The two finest diamond certificates and grading labs that we recommend are the GIA and the AGS. The AGS triple zero ideal and GIA Ex/Ex will be discussed later in these diamond tutorials

Deep Cut Diamonds

It's easy to see that the deep-cut diamond shown above will have a higher carat weight, but is clearly the less desirable stone! Many jewelers will not discuss cut proportions unless the customer specifically asks; a stone rich in carat weight but poorly proportioned can be deeply "discounted," giving the buyer a false impression of a great deal.

In a poorly cut diamond, the light that enters through the table reaches the facets and then 'leaks' out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less brilliance.

Shallow Cut Diamonds

It's easy to see that the deep-cut diamond shown above will have a higher carat weight, but is clearly the less desirable stone! Many jewelers will not discuss cut proportions unless the customer specifically asks; a stone rich in carat weight but poorly proportioned can be deeply "discounted," giving the buyer a false impression of a great deal.

In a poorly cut diamond, the light that enters through the table reaches the facets and then 'leaks' out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less brilliance.

Proportions

Gemologists agree that the best cut diamonds are those that follow a set of formulae calculated to maximize brilliance. These formulae can be seen in a diamond's proportions, most importantly how the depth compares to the diameter, and how the diameter of the table compares to the diameter of the diamond.

However, the variance in the proportions between an Ideal Cut and a Poor Cut can be difficult to discern by the casual observer.

Because cut is so important, several grading methods have been developed to help consumers determine the cut of a particular diamond. In general, these grades are:

Ideal
Premium
Very Good
Good
Fair & Poor

Selecting the grade of cut is really a matter of preference. To make the best selection, you need to understand the various grades. Please note that the descriptions below are general guidelines.

Ideal Cut
This cut is intended to maximize brilliance, and the typically smaller table sizes of these diamonds have the added benefit of creating a great deal of dispersion or 'fire' as well. Ideal quality diamonds are truly for the person who enjoys knowing that he has one of the finest things that money can buy. This category applies only to round diamonds.

Premium
In the case of round diamonds, many Premium Cut diamonds have cuts that are the equal of any Ideal Cut diamond, though they often can be purchased at slightly lower prices than AGS Ideal Cuts. They are intended to provide maximum brilliance and fire. Like the Ideal Cut, these are also for the person who enjoys knowing that he has one of the finest things that money can buy.

Very Good
These diamonds reflect most of the light that enters them, creating a good deal of brilliance. With these diamonds, the cutters have chosen to stray slightly from the preferred diamond proportions in order to create a larger diamond. The result is that these diamonds fall slightly outside of some customers' preferences in terms of, for example, table size or girdle width, though, in many cases many of the parameters of diamonds in this range will overlap with certain parameters of diamonds in the Ideal or Premium ranges. Generally, the price of these diamonds in slightly below that of Premium cuts.

Good
Diamonds that reflect much of the light that enters them. Their proportions fall outside of the preferred range because the cutter has chosen to create the largest possible diamond from the original rough crystal, rather than cutting extra weight off to create a smaller Premium quality diamond. Diamonds in this range offer an excellent cost-savings to customers who want to stay in a budget without sacrificing quality or beauty.

Fair & Poor
A diamond graded as fair or poor reflects only a small proportion of the light that enters it. Typically these diamonds have been cut to maximize the carat weight over most other considerations. Most of these type of cut diamonds can be found in retail mall jewellery stores.