The CUT of a Diamond

MAB DIAMONDS...Ideal cut diamonds, gold, jewelry, 14 and 18 karat gold, platinum, rings, designer estate and custom jewelry for the educated consumer. Member American Gem Society. Located in Springfield, Pennsylvania, in the heart of the Delware County.

All About the Cut of
A Diamond

When a round brilliant diamond has been cut to "Ideal" proportions
by a master cutter, it is a splendor to behold.
The Ideal Cut Diamond describes a round brilliant diamond that has
been cut to exact and mathematically proven proportions. Its
symmetry, with 58 exactly placed facets, produces the ultimate
in lustre and beauty.
When a diamond is cut to the ideal proportions, all of the light,
entering from any direction is totally relfected through the top and
is dispersed into a display of sparkling flashes and rainbow colors.

A Premium Cut (or near ideal cut) diamond demonstrates subtle variations from the Ideal Cut.
Although dimensional differences affect a diamond's reflection of light,
a Premium Cut still achieves a harmonious balance between its proportions
and the display of brilliance.

(Arrows on the diagram simulate the flow of light in the diamond)

The Ideal Cut
Light entering the diamond
reflects internally from facet
to facet and is relfected back
through the top ONLY, creating
maximum brilliance.

Inferior Cut
Most diamonds are "spread" in their cutting to retain maximum
weight from the original rough. A heavier diamond will result,
but at a dramatic sacrifice of potential fire and brilliance.

Too Deep
When a diamond is cut too deep,
light leaks out of the bottom,
brilliance is lost and the center
of the diamond will appear to dark.

Too Shallow
When a diamond is cut too shallow,
light leaks out of the bottom,
brilliance is lost and the diamond
appears watery, glassy and dark.

The diamgram below shows how light, coming in from the human eyes perspective, refracts within the diamond and then exits according to the cut of the crown.

What Is Cut and How Is It Graded

Cut is the only value factor that can be controlled by human hands. The qualities of a diamond in the rough can only be brought out by the work of a skilled artist. Before you see a sparkling diamond under the lights in your local jewelry store, it has already been shaped to stringent specifications by a skilled artisan, and given its beautiful polish.

The goal of the expert diamond cutter is to fashion a diamond that produces the most satisfying return of light to the eye within a pleasing symmetrical shape. All the while, the cutter is balancing the goal of attaining maximum brilliance and symmetry against the inevitable loss of weight necessitated by the very process of cutting.

Symmetry plays an important role in how light is returned to the eye, but it is also a characteristic to be considered on its own merits. Think of it as how closely the right side of the stone matches the left. Imagine placing a mirror on an imaginary line that runs through the center of the stone. The image in the mirror would correspond exactly to the half of the stone it reflects. In a perfectly symmetrical stone, the left and right side of the stone would be like mirror images of each other.

In addition to proportion and symmetry, how the diamond is polished affects the final cut grade, too. A well-polished diamond produces sharp sparkle and undistorted brilliance and fire. By contrast, even a well proportioned, symmetrical diamond can look dull or fuzzy if the polish is poor.

The most exquisitely cut round brilliant diamond, called the "ideal cut',' earns a 0 cut grade on the AGS Diamond Grading Scale of 0-10. The 0 cut grade is reserved for those round brilliant diamonds which conform to the cut dimensions calculated to produce maximum brilliance with a high degree of "fire" for the most beautiful return of light to the eye. It is a rare diamond that adheres absolutely to these rigorous standards. But the grades between 0 and 10 represent a broad spectrum of cutting characteristics for you to consider.