First, don't confuse diamond "cut" with "shape."
Shape refers to the general outward appearance of the diamond,
(such as round, emerald, or pear). When a diamond jeweler (or
a diamond certificate) says "cut," that's a reference to the diamond's
reflective qualities, not the shape (or at least it should be,
we have found that even some "jewelers" don't appear to know the
difference between "cut" and "shape").
Diamond cut is perhaps the most important of
the four Cs, so it is important to understand how this quality
affects the properties and values of a diamond. A good cut gives
a diamond its brilliance, which is that brightness that seems
to come from the very heart of a diamond. The angles and finish
of any diamond are what determine its ability to handle light,
which leads to brilliance.
When a diamond is well-cut, light enters through
the table and travels to the pavilion where it reflects from one
side to the other before reflecting back out of the diamond through
the table and to the observer's eye. This light is the brilliance
we mentioned, and it's this flashing, fiery effect that makes
diamonds so mesmerizing.
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
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
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:
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.
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.
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.
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.
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.
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